snippet
stringlengths 143
5.54k
| label
int64 0
1
|
|---|---|
I'm looking for open books on abstract algebra, other than Judson's AATA. I want one with a good number of exercises (and solutions, preferably), this one covers the rest. Does anyone know of one? This and this are similar questions. The first one has many answers and the second is markedly different, but answers specific to abstract algebra, with brief descriptions of each book (too much to expect in the first) might help someone someday. | 0 |
So I was wondering if it was possible to prolong the "entropy" of the bottle by making sure the heat of the contents of the inside of the bottle doesn't escape by first having a secondary bottle on the inside of the existing container. Then there would be a vacuum. So would the heat stay trapped if there were mirrors on the inside of the outer container bouncing infared radiation as it gets radiated from the inner container. Is this a means of preventing entropy increase in the universe, so could be used with dyson spheres to trap heat preventing it from escaping in the distant universe to preserve more energy? Are there any issues with this approach? | 0 |
According to numerous questions (e.g Is it recommended to use "we" in research papers?), one should use "we" instead of "I" while writing a scientific paper. However, it's unclear to me if, for example, "In the following image you can see..." should be replaced with "In the following image we can see..."? Personally I think, that the latter sounds better and also includes the reader together with the authors in the discussion at hand, as already mentioned in the above question. But it's still unknown for me, if it could or should be mentioned while reviewing another paper. | 0 |
Superdeterminism is one wild conjecture which is an alternative to the standard quantum mechanical interpretation and preserves local realism Superdeterminism seems to be too much of a stretch. If experimental results are pre decided it simply renders the experiments useless. Is there any alternative in the academia where something like minimal determinism is discussed? Like just the minimal amount of determinism needed to retain local realism. For eg: In the classic Bell's test, if the entangled electron pair generator knows the direction of measurement of spin beforehand for even one of the electrons while generating the entangled pair of electrons, hidden variable theory can violate Bell inequality. Instead of the entire system being superdeterministic, only one pair of entangled electron pair generator and electron spin detectors are determined. | 0 |
I'm looking for a single word that means "to bring within reach"/"make possible" for a technology or promising development. For example Mobile phones _____ photography for the common person. "Facilitate"/"make accessible" isn't quite right - I want to convey a step change, a paradigm shift. In particular, I'm naming a business. I work in robotics. Robotics has long been touted as a way to give people mobility, automate the mundane, and facilitate humans focusing on what matters to them. My goal is to build tools for other companies to accelerate them and _____ the promises of robotics for humanity. | 0 |
I work in STEM and a problem I often face with is the use of "by" or "through". Let me explain it with an example. I have a quantity named "variance" that is derived after a certain number of tests (called Monte Carlo simulations). So, I write it like the following: The performance of the estimator is evaluated by comparing its numerical variance with other estimators obtained by/through Monte Carlo simulations. | 0 |
this was my first question here and I asked it before I knew anything about this site like the dup questions I want resources (books) for studying Euclidean geometry beyond the high school level. I have been searching for good books on this topic but haven't found any. Could you please provide me with recommendations or suggest good books for this subject to study it in more depth than high school geometry? | 0 |
So, back in my school, our teacher was teaching structure of an atom. I had some doubts, like why do hot objects emit radiations and so many. I noticed that every question I had asked had an answer. If I added a why to it, thats another question. It mostly came to a conclusion that all atoms want to attain stability. My question is why atoms want to attain stability and can I relate it to entropy? | 0 |
How is this construction correct? The drawing-room began to look empty: the baccarat was discontinued for lack of a banker; more than one person said goodnight of his own accord, and was suffered to depart without expostulation; and in the meanwhile Mr. Morris redoubled in agreeable attentions to those who stayed behind. (Robert Louis Stevenson) In my humble opinion, the correct sentence should be: ... banker; more than one person said goodnight of his own accord and was suffered to depart without expostulation; .... We are not supposed to use commas when a second verb (was) has the same subject as an earlier one (more than one person). Of course, my problem lies only in that part of the brief. | 0 |
I am looking for a word for an environment where people feel choked. For example, the environment in medieval Europe (or in communist era) was far from free. One felt choked/strangulated. Is there is word to describe such an environment? For eg, for happiness, one could say An era/regime of happiness. What would that be for choked? Update: I was trying to say that the age of Enlightenment was a response to a 'choking kind of environment' where the church had too much control over people's lives. | 0 |
Whenever there is contact between objects, there exists a normal force. If we apply force on an object, our hands are in contact with the block, so there will be a normal force on my hand and normal force on the block, so the net force acting on the block will be the applied force plus the normal force. Why don't we include the normal force acting between our hand and object? | 0 |
I've seen a lot of proofs of the convergence properties for the Fourier series of continuous periodic functions that use the assumption that the function's derivative and second derivatives exist and are also continuous. I was wondering is the stipulation that the derivatives exist considered not that restrictive of an assumption because we can consider the Stone-Wierstrass polynomial approximation of the function instead which converges uniformly to any continuous function on an interval and does have continuous derivatives? | 0 |
According to Transformation of the energy-momentum tensor under conformal transformations The schwartzian term in the transformation properties arises due to the stress tensor being defined as the normal ordered classical expression, where the normal ordering happens with respect to the given coordinate frame. However, the infinitesimal transformation properties of the stress tensor can also be derived in terms of conformal Ward identities. I think it is kind of magical, that apparently the derivation in terms of the path integral "knows" about the appropriate change in normal ordering under coordinate transformations and I wanted to know, why the path integral implements the right normal ordering procedure, without having somehow incorporated it explicitly? | 0 |
I'm writing a book using the book document class and, for whatever reason, one of my chapters has its contents start on the next page rather than the current page. I have no idea why this is; I looked for manual page breaks or anything that might be causing an issue to no avail. Each chapter is broken up into a .tex file that inputs other sub-chapter .tex files. So, I'm not really sure what to post as far as a MWE since this issue plagues exactly one chapter. Is there some arbitrary setting or command that I accidentally enabled that does this? "Broken" chapter: Example of a "correct" chapter: | 0 |
In The Symmetric Group the author, Bruce Sagan, uses the terms degree and dimension of a matrix representation synonymously to mean the number of columns of the matrices. However, I have also seen elsewhere that the degree has been defined as the number of columns in the matrices, whereas dimension refers to the dimension of the vector space on which the group acts. I guess the author can define the terms how he wants, but is there a convention for what these terms mean more precisely? | 0 |
For an animation with TikZ and Asymptote (that I am somehow familiar with), its size is accumulative with the number of steps. I am mimicking animation for From Random Polygon to Ellipse, take a polygon with random vertices, find the mid-points of its sides, and use these to create a new polygon, replacing the original. Do this repeatedly and an ellipse will eventually form. See here for more explanation. In this situation, the number of steps/frames is large or extremely large, and only last step/frame is needed. Can we do it with TikZ or Asymptote? Do you have any other recommendation? PS: I can add a MWE with TikZ/Asymptote, but as said above, I think it is useless. | 0 |
I am creating fill-in the blank notes for my class using the Censor package, a solution I found on this forum here. What I can't figure out is how to make the blanks for my students to fill in longer -- ie, I don't want text to be ____ but more like ____________ since most people don't have tiny, perfect handwriting. Is there a way to add a multiplier to the length of the blank or replace a character with, say, two or three underscores instead of one so that normal people can fit their handwriting in one of the blanks? If someone has a different, cleaner solution that would be great too; the post explains the gist of what I need to do. | 0 |
I am searching for the title and author of a book once lent to me. I cannot recall much about it other than the color scheme used on the cover. The cover was black with orange lettering. Perhaps there was a gray strip at the very top. It looks somewhat like this cover. However, as I recall, the book had some depiction of a matrix on the front cover. The title had Matrix or Matrices in it. Perhaps Theory or Applications. If anyone knows what book I may be thinking of, a citation would be very appreciated. | 0 |
Consider the above diagram. I am currently learning about standing waves in an open and closed tube. To me, it is trivial why at a closed end, there must be a node, as particles are not free to move around back and forth. However, to me an open end is not so trivial. Why must it be an antinode rather than some other part in the wave? | 0 |
Could someone help me constructing such segment AB in Geogebra that would satisfy such properties: by moving the point A the segment moves as a solid body but does not rotate by moving the point B the segment changes its orientation and size the segment should be able to move like a solid body even if one of its edge points is attached to a line I have already tried to use vectors but got the result that don't satisfy those properties above. | 0 |
I am wondering if an incident gamma could compton scatter from the delocalised pi-electrons in an aromatic compound (e.g. liquid scintillator). I understand that compton scattering is valid for free electrons, and is usually described in terms of the outer most atomic energy levels where incident photon energy >> binding energy. However, how about compton scattering from molecules, and particularly delocalised electrons in aromatics? Furthermore, if it is possible, would the scintillator be excited and scintillate after a pi electron is removed? Thanks! | 0 |
The following are the formatting guidelines for citation call-outs and formatted bibliographic entries provided by the journal International Economic Review: Unfortunately, the journal does not provide a BibTeX bibliography style file that would implement these guidelines, and no template is avaibable in https://www.overleaf.com/learn/latex/Bibtex_bibliography_styles. I was wondering whether there is an encyclopedia of bibliography styles that I could choose from. Or, how shall I customize it by myself? | 0 |
basically the problem is the same as in a question i previously asked: Draw shaded region using tikz and pgfplots Now the problem is that the region i want to draw is more complicated, mainly because of the functions involved: This is what i want to obtain, but i don't know how to change the code in the answer in order to draw the graph showed in the image, also because tikz does not really get along with sqrt function. Does anyone know how to solve my problem? | 0 |
There are many methods for diagonalizing matrices; probably the most widely used is the combination of household transformations and the QR algorithm. Is there any superior method for diagonalizing large, non-sparse real symmetric matrices? Superiority can be a bit muddy, so I define it as fast, numerically stable, does not require large amounts of extra memory, and lends itself to parallelization and vectorization. Crosspost: SciComp.SE | 0 |
If a stationary charge is kept in front of current carrying wire , from charge's perspective the protons are at rest with it and electrons are moving , so shouldnt there be a lenght contraction in electrons and there density increase and stationary charge should feel a force , but it is seen that it doesnt?? please answer the question in stationary charge's frame of reference when electrons are flowing in the wire | 0 |
It doesn't have to be a MacBook exactly, other switched power supply powered metal case devices are good enough, but MacBook is the most common. It must be AC powered; the effect disappears when unplugged. Your other hand (which doesn't slide on the surface) must not touch the surface; the effect disappears when touching the surface with the other hand. You must move your finger; the effect disappears when you stop. The same effect can be felt by sliding on someone else who touches such a device. It's definitely not a potential difference. I suppose it's mechanical resonance, but can't explain. | 0 |
True or false question! Conduction is the slowest mode of heat transfer - true (given in internet) Now my question is, let's say you want to boil some water, in this case should not be the conduction mode be faster than convection? I mean within seconds, we can feel the heat energy if we touch that beaker, where we need some time to feel the same amount of heat energy from water. Kindly elaborate on this. | 0 |
Let there be some air contained in a vessel whose walls are elastic. The vessel is closed and we impart some velocity to it. Please note that the gas inside the container is stationary w.r.t. the container. But the container, itself, is moving with some acceleration. The gas particles should press against the walls in a direction opposite to the direction of motion. My question is can we say whether the internal pressure created by the gas particles increase or decrease with increase in the acceleration of the vessel? | 0 |
The electrons in the hydrogen molecule experience the same potential and are thus in the same state, so the Pauli exclusion forces them to have opposite spins. Since the protons are identical by symmetry, are these in the same state too? If they were, then the spins would be forced opposite and orthohydrogen would not exist. So in what way am I thinking about this wrong? Is it that the ground state for the protons is degenerate? | 0 |
Aperiodic tilings for the plane are quite popular. I can't find any papers on aperiodic tilings on infinite surfaces like a cylinder. One reason might be that these are no longer called tiles but something else (a curved finite surface). Do references for this exist? Periodic tilings of cylinder can easily be accomplished with a machine: https://en.wikipedia.org/wiki/Knurling A lathe machine has parts that rotate and easily create a periodic pattern that has one tile type. Not sure if there exists a machine that would do it with multiple tile types. My end goal is to find a similar method to aperiodically tile a cylinder. At least one part of rotation would have to exhibit aperiodic behavior, but I leave that outside of the scope of this question. | 0 |
If we have a set of sentences S in first order logic. We know that we can create a first order theory Th(S) from S, which is the "set S" union "the sentences which we can prove them from S" . Also as first order theory, this theory follow the rules (axioms and rules of inferences) of first order logic. Does it has sense to define the Th(S) as above but with an extra union with "axioms of first order logic" ? Also can i consider the Th(S) as formal system which has "intersection" with the formal system First Order Logic? | 0 |
In Bell's Spaceship Paradox, are there any direct observations that the stationary observer can make that would justify the breaking of the string without taking into consideration as to what's taking place in the frames of the ships? In other words, can it observe any changes in the string's properties that would justify the break without having to switch or calculate in other frames? If the string is replaced by a bar that can stretch a bit before it breaks, in the rocket's frame it would appear that the stripes become broader before the bar breaks. What would the stationary observer observe? | 0 |
Can the longest length of a regular icosahedron be equal to the longest width and the longest height? Since the icosahedron is regular, this would mean its faces would still have to remain as equilateral triangles. If this is not possible, are there any ratios between length, width, and height? As a follow up question, can we use edge lengths to determine the length, width, or height? Are there any possible equations? | 0 |
Example: She ate one or more apples, and each apple of the one-or-more apples was either red or green. In the example, if "one or more apples" is the antecedent, should the reference back (i.e., "the one-or-more apples") be hyphenated? My thinking is that "one-or-more" in "the one-or-more apples" works as a compound adjective or "compound quantifier" when referring back to the antecedent of the example, and hyphenation of the compound adjective or quantifier improves readability. Readability is not an issue in the example, but repeated references back to such an antecedent with the hyphenation seem to be easier to read in longer forms of writing. | 0 |
I understand "what (a) nerve!" means "how rude". I somehow always thought "what a nerve" is more common and was surprised at the exchange made in this question. Apparently American English speakers feel "what a nerve" is strange. My questions: Is it correct to think that the difference is regional? More specifically US/UK? If there are native speakers from other countries, how do you feel about "what a nerve"? | 0 |
A vertex is defined as a 'meeting point of two lines that form an angle'. When I increment the circumference of a circle into infinitesimal small increments I get something like shown below in the picture. This infinitesimal small increment of the circumference can then be divided into left and right which is shown by the black arrows in the picture. My question is, if the part of the circumference is infinitesimal small, the left and right part of it would not be curved and therefor the above mentioned description of a vertex would be true. | 0 |
I have heard of definitions along the line of saying that a transformation T of something with respect to a certain property p is symmetric if, after T is applied, p remains unchanged. Is there a way of refining this definition? How could you use this definition to show that fractals are symmetric? What are T and p? If something satisfies a recurrence relationship, is that a type of symmetry? ################################################## From the comments, I am getting the impression that there is no specific definition of mathematical symmetry. Fractals are frequently described as being highly symmetric. The idea is that you can uniformly contract or expand a fractal and lay it on top of itself. | 0 |
Given a stochastic differential equation SDE the mathematical definitions are clear to me, i.e. we want to find a filtered probability space, a BM and a process which satisfy the SDE. However in the real world we are given a probability space and a BM on it (e.g. the uncertainty on the stock market). Why constructing these weak solutions which are purely mathematical objects would help? | 0 |
When two black holes are merging, one of them can be ejected if it has less mass than the other black hole, so the gravitational waves emitted by both of them is unbalanced, and the more strong ones would "kick" the smaller black hole out of the merger, sometimes even kicking it out of the galaxy. This is known as gravitational recoil. Can this also happen with other objects like stars or planets so that they can get ejected to very high speeds? If not by the same mechanism, maybe through a similar one? | 0 |
Newb here. When I look up how to create two columns, I get a bunch of tutorials that assume one text will run from the bottom of column A to the top of column B, like a newspaper article that spans two columns. That's not what I want to do. I want to put one text in the left column, a different text in the right column. Like two separate newspaper columns. When the text reaches the bottom of column A, instead of picking up at the top of column B, it should start at the top of column A on the next page. | 0 |
This is not a hint-to-solve-exercise question, but just mathematical curiosity involving one my favorites branches of this beautiful science: group theory. Having done some research in databases like this one, I came across with some different ways to construct groups of a given order. Since I don't know about extensions, my knowledge is more limited but I have a question: how many "different" group/subgroup products are there? In the database I wrote, I found things like "central product", "wreath product" (apart from the typical direct or semidirect ones), etc, but, are these products the only constructions? Am I missing other types of products? | 0 |
As I wrote in the question, what is thermodynamic equilibrium? From what I understand is a state where the thermal, chemical properties don't change with respect of the time and there is a mechanical equilibrium as well. But can this be true for example, in a body with a temperature field with gradients? I was reviewing this concept because thermodynamic equilibrium is critical in defining a reversible process and I want to understand it well. | 0 |
I have a presentation with one of the slides titled Results: limited-data in-the-wild semantic segmentation What would be the correct way to capitalise this title? https://capitalizemytitle.com/style/APA/ recommends either Results: Limited-Data In-The-Wild Semantic Segmentation or Results: Limited-Data In-the-Wild Semantic Segmentation with the latter of the two being the one I originally used. However, this seems to be in conflict with the recommendations from this question, which say words like "in" or "the" should never be capitalised. | 0 |
Imagine if a box tied on string is swirl around a rough surface. The centripetal force might be contributed by both tension and friction. Since the surface of the object is flat instead of spherical surface, it might not rotate along its motion (rolling like a tyre). So, what type of friction should we consider that contribute to centripetal force?Is it static friction or kinetic friction | 0 |
I know that: At this time tomorrow, I will be playing cricket. is used since the so-called future continuous is used to talk about a continuous activity at a specific time in the future. Even present continuous is used to talk about a planned activity in the future. So my question is can we say this? At this time tomorrow, I am playing cricket. I am eagerly waiting for the scholars' or experts' comments on this. | 0 |
I was looking at the modeling of ttW production (but the question is general) and came upon an off-shell corrections paper. As I am no expert on MC generators, I am not sure if these off-shell corrections can lead to different amounts of radiation compared to an on-shell sample. My intuition says that maybe a Sudakov factor contribution might shift slightly and because of the Pt shift of jets the PS might differ but I do not expect large differences in number of jets as I can't think of an off-shell channel diagram that would differ significantly in extra radiation. Is this the case or are there examples where one does see noticeable differences (only in the modeling/in data as well)? | 0 |
The narrator in this video has a very clear native English accent. What caught my attention is near the end of the clip when he said: They spend so much time in the tree and they sleep while hanging upside down like a bat. Though I know that it's grammatically correct to compare a plural noun with a singular noun, such as: They are much slower than him. Or: They ran as slow as a turtle. However, I am still wondering how often (or rare) for native speakers to compare many "lemurs" with plural "bats" instead of a single "bat" in the first sentence, or at least isn't it abnormal to do so? | 0 |
In an attempt to understands some basic concepts about manifolds and differential geometry I encountered a concept of a parallel transport. This perhaps may be very naive question, but could one consider an analogy to the parallel transport (as defined in this Wikipedia article) being a ball rolling on a flat table surface? If so, is then such an example also an example of holonomy or not? | 0 |
Recently, I was attempting to describe the experience of traveling with strangers on one of those pedal trolleys which serve beer - how producing physical effort with others towards a shared goal inspires fraternity or camaraderie. I did some googling for inspire synonyms and a few searches along the lines of inspiring fraternity, but haven't been able to find the word I'm looking for. It would be a synonym of inspire, with this added connotation of specifically inspiring fraternity. Example sentence: Digging a ditch with another man ____ between the two of you. Any clever linguists know a single word to describe this? | 0 |
I understand that a taylor series is used to approximate a given function at a point to any required degree of accuracy, I have not however understood why when we take the taylor series of a function at point, expanding to infinite terms it perfectly represents the function over the entire domain of the function. Is there a mathematical proof for why this results from approximating a function and its infinite derivatives at a single point | 0 |
If you have a point mass moving with some velocity 'v' and then a force is applied perpendicular to 'v', physics/mathematics claims no change in the magnitude of 'v' , just a change in direction. But that doesn't make intuitive sense to me because wouldn't a force cause an instantaneous change in the point mass velocity perpendicular to 'v'? Therefore, wouldn't there be instantaneous velocity vectors perpendicular to each other and a resultant vector with a greater magnitude than 'v'? | 0 |
My professor was discussing this question. After finding out that CR equations are satisified at origin for the function he used the definition of derivative to check for differentiabilty. Also, he mentioned that we can't compute partial derivatives of u(x,y) and v(x,y), and for example one of them turns out to be discontinious at origin then say that the function is bot differentiable. I couldn't understand his reasoning. Isn't that the sufficient condition for differentiabilty?Thoughts? Click here for question | 0 |
I'm trying to write a book (documentclass "memoir") and I would like each chapter to begin alternatively with a greek or arabic letter. I have no problem with greek thanks to the package "babel", by contrast whatever attempt to write a-single-arabic-letter creates big conflicts in my template, such as compiling errors, and other problems (such as, the letter is automatically written on the right hand side: and it makes sense, of course, but I just need it as a symbol). I've looked through many other questions, which usually concern writing sentences, and I wonder if there is a simpler method that fits my case. | 0 |
The way I have it is: the Observable Universe looks as follows. In some ball, all the galaxy clusters exist, then in a bigger concentric ball the dark ages exist (no galaxies), then on the surface of this larger ball at the edge of the observable Universe the Cosmic Microwave Background exists. This leaves no room for an infinite or curled back on itself Universe, so it must be a wrong picture. How do you picture it? It would be advantageous to get a correct picture. | 0 |
When submitting a memorandum request for approval of something and providing options of for the signer... what is the best way to word the denial option ? Disapproved? Denied? Unapproved? This is intended to allow the approver to circle their response. Approved / Denied Approved / Disapproved Approved / Unapproved I feel disapproved is not the correct word... since they may disapprove of the request in theory but that doesn't mean they're saying no to the action. Denied seems to be more definitive. Unapproved works but seems lackluster in some way and may indicate the action was taken without prior approval or something similar to that. | 0 |
I am writing my Doctorate thesis in Latex. I am using book class, which by default is twoside and openright. But for the preliminary pages, specifically for page number ii, certificate, it needs to be printed on a new page, but the result is coming out as a larger right-side margin page for being an even-numbered page. The same problem arises for the list of figures and tables also, they are also starting on an even page and the output is a bigger right margin. Please help to overcome the situation. Thanks in advance. | 0 |
I'm doing undergraduate research on the history of Abstract Algebra (specifically permutation groups) and the notion of symmetric groups in indigenous artwork has come up several times. Is anyone aware of evidence of this 'intrinsic' human desire to construct groups I could point to? Or maybe some natural phenomena that conform to the definition of group? I'd like to have specific examples I can explain (and possibly map some ideas of formalized group theory onto). Thanks! | 0 |
So I had taken a course on BEC and Cold Atoms. I have read about the properties of non-interacting Bose gas and I was a little concerned about what we mean by two wave functions (of bosons) being the same. Does it mean that they are physically located at the same point in space? I understand that they have the same spatial probability distribution. But it is more than that. I basically want to know given two wave functions how do I say they are the same? A more physical meaning of two wave functions being the "same". P.S. This is my first time posting. So please be kind. | 0 |
Regarding an acceleration in an empty universe, from the special relativity we feel an acceleration in an empty universe since there is still the presence of an space-time with respect to which an acceleration is measured and the equivalence principle says that locally the effect of gravity and acceleration is indistinguishable i.e we feel the gravity whenever we are acceleration and conversely we feel acceleration when there is gravity that means according to equivalence principle we can't feel an acceleration in an empty universe since there is no gravity but special relativity says that we can feel an acceleration in an empty universe ,for me there seems a contradiction between special relativity and equivalence principle. Does anybody make clear this doubt? | 0 |
I imagine a swinging pendulum being held outside a black hole supported by the normal foce of a jet propelled rocket. The rocket's velocity is approaching light speed, therefore hovering the swinging pendulum right above the event horizon in the strong gravitational potential outside of the black hole. My first question is: what would the frequency be of this pendulum and would this be the natural limit to swinging frequencies? How could the frequency possibly increase more in potential in nature (besides by shortening length)? And following the consequences of this: I believe photons and pendulums behave identically under the influence of a gravitational potential; does this then imply photons also have a natural cut-off limit for their frequency? | 0 |
If I have an action that is not invariant under a change of coordinates. Does this effect the renormalizability of the theory? The procedure of renormalizing a field theory essentially boils down to carefully keeping track of observables while changing the length scale of the theory. If I have an action that is not diffeomorphism invariant changing the scaling of the action has physical meaning and also has consequences on the parameterization of the theory. How does the renormalization process differ between actions with and without coordinate invariance? | 0 |
My electromagnetic waves professor said any time an electromagnetic signal is received by an antenna, a transmission also occurs. I have not independently verified this, but I believe it is likely true. Does someone know if this is true, and can the basic physics be explained, please? Note: This question was inspired by my own comment on Antennas and relativity. I'm thinking of this more from a Maxwell's equation POV then relativity, however. ANOTHER NOTE: Per comments below, transmission is usually called "scattering" when unintentional. | 0 |
As an example, why does glass tend to break by means of intergranular fracture? My analysis so far led me to believe that the tendency can be related to the intermolecular bond strength in a given crystal grain and the intergranular bond strength. A stronger bond means that better load bearing. If the intermolecular bond is stronger than the intergranular bond, then a material is more likely to experience intergranular fracture. But is this correct? | 0 |
So, I know the proof for Halting Problem is not recursive using diagonalization. We prove it using proof by contradiction. First we assume HP is recursive which implies there is a Total Turing Machine. And prove it is not possible by contradiction. But the proof just says Halting Problem is not recursive. It doesn't say Halting Problem is recursive enumerable. So how to prove Halting Problem is recursive enumerable | 0 |
So in math, analysis in particular, divergent series are not particularly interesting since most sequences are divergent. However convergent series are interesting and they are useful. However, mathematicians have realized they had to be careful and define two types of convergence. Most of the theorems rely on absolute convergence. Therefore my question is, if your series turns out to be conditionally convergent, are you stuck? That is, can you not conclude anything further or can you still work with a conditionally convergent series? | 0 |
Consider how the wizarding world is hidden from the muggle world in the Harry Potter/ Wizarding World universe. Or in Hell Boy II. The troll market is hidden under a bridge. Red can see it but it's veiled from the human eye. Shadow Hunters. Clary can see the runes outside of the nightclub but Simon can't see them. I have been referring to it as a troll market concept but I feel like there is a better word(s) for it. | 0 |
So , I will be completing S.L Loney Coordinate geometry book very soon and I feel like I need more practice in Conics especially in Ellipse and Hyperbolae section , Can anyone suggest me a problem solving book in Conics (Not theory, Because S.L loney has a very vast theory and sufficient for my preparation) and the level of the book must up to a competitive level exam or Olympiad. Thank you:) | 0 |
From Boston Legal (or your everyday conversation): "He and I will be going on a little vacation." "Where?" "Probably best you don't know." Being short for "It would probably be best if you didn't know," the spoken version changes the past tense to the present in the second half of the sentence. Is this something a grammarian would find fault with? Or dismiss it as colloquial? | 0 |
From how I've learned it in school the magnetic vector potential is used as a mathematical tool to simplify problems with current-carrying wires in classical electromagnetism, but is never treated as bearing any physical meaning. After doing some research on it myself, I found Feynman's lecture on the subject, which outlines how this vector potential actually takes center-stage in QED, not only featuring in its primary equations for concepts like phase change but also as capable of producing physical changes such the Aharonov-Bohm effect that can't be explained by the magnetic field alone. Are there any comparable physical effects the vector potential has in classical electromagnetism? | 0 |
I understand that thunder clouds are a congregation of millions of water droplets. As water evaporates from the ground, these water molecules rise up and collide with water molecules of the cloud, sometimes ripping off electrons. This creates a seperation between positively charged water droplets moving up inside the cloud, leaving electrons behind. Why do the electrons stay at the bottom of the cloud and not move up due to attraction to the positively charged water droplets? | 0 |
I'm new to fractals and especially the Mandelbrot Set. I've noticed these never ending and self-similar spirals all around the Mandelbrot set, just like the one below: At lower max-iterations, there is a black point in the middle of the spiral, which suggests me that there could be a minibrot there. I've read that minibrots are centered on c values with super-attractive orbits. However, since the spiral never ends, I cannot precisely get the middle point and calculate its orbit. Is there really a minibrot infinitely small at the end of the spiral? | 0 |
I've been learning about set theory and have heard of something called a "group". I didn't understand what it was, even after researching it, but I did find out one piece of information: All groups are sets but not all sets are groups My question is: what is an example of a set that is not a group? That would help me better understand it. | 0 |
More precisely, "to" is banned in the active form: The headmaster makes us honor our teachers but required in the passive (with no agent stated): We are made to honor our teachers I can just say it's something -- for lack of a better term -- mechanical: "to" is required to mark the infinitive in the passive voice. But then, why does "mechanics" matter in the passive voice but not in the active voice? More puzzling is that this phenomenon seems to apply to causative make, but not to causative force: The storm forced me to seek shelter I was forced (by the storm) to seek shelter Unlike make, "to" is required in the active voice of force. Thank you. | 0 |
Imagine a stationary transmitter which vibrates the surface of the balloon and a stationary receiver half way around the balloon that can pick up these waves. Let the balloon expand. Will the frequency of the received waves change due to a Doppler effect? As the balloon expands, the tension in the surface will increase which could alter the velocity of the waves. This is not a Doppler effect and could be allowed for. I ask the question because the motion of both the source and the receiver due to the expansion is perpendicular to the direction the waves are travelling in, though there is also a velocity of recession, which is different to the velocity of expansion. | 0 |
In the same context as of "Trendy names", why is "Brandy names" not used? Brandy comes naturally/intuitively as an adjective to brand in the minds of a new English speaker, instead of the commonly used words like brandworthy, brandable, branded. I want to understand the reason behind such usage. If we assume the word brandy does not denote a specific alcoholic beverage, is it grammatically correct to use "brandy" as an adjective of brand? | 0 |
What are the different methods using contour integration that can be used to count the non-trivial zeros of the zeta function? I know of Backlund's exact formula which is similar to Riemann-von Mangoldt formula. What are the other ways? If there aren't many other different methods, then where can I find the exact derivation, like from scratch to end of Riemann-von Mangoldt formula? I have managed half of it till the point I can derive Backlund's exact formula. Also an evaluation of the limitations would be nice. I know Titchmarsh's works are useful but what other resources can help me? | 0 |
In the sentence: "There were people everywhere. They thronged the streets, choking the alleys. They had come in their thousands to see the light show" I would group the infinitive of purpose and past perfect together, so that the sentence refers to a plan formed prior to the events of the story. At the same time, the arrival itself takes place before the crowds assemble and begin 'thronging'. Is my analysis off? EDIT: I apologise. I had to cut this short before clarifying. The sentence seems to be referring both to the arrival and a preformed plan. | 0 |
I'm trying to prove the above statement, and I had a look at this site. This ends the proof with the following statement the rank is the number of non-zero eigenvalues But, this is what makes me confusing, because it's not all the case that rank of a matrix equals the number of non zero eigenvalues as far as I know. This shows a counter example of this. Any comment about the rank of idempotent matrix would be grateful. | 0 |
I understand the general notion of twist like that of a mobius band(like a cylinder cut open and the glue the edges together with a "twist") , and the torsion in the context of algebraic structures like groups, in which a modulo-n torsion indicate when we multiply some element with n, we get the identity(please correct me if there is an error in my understanding). So in the context of topological groups, can these ideas be related, like in the case of a lie group, where we can talk about both twist and torsion and whether these ideas turn out to be related? | 0 |
I want to add a citation inside a pdf figure, and would like the citation to be a link to the bibliography. I know embedding a pdf with includegraphics normally mangles the link, but I have found a solution (in pdflatex), using the pax package. But am open to any other solution. pax preserves the hyperlink, and I tested it is working with a www address. But for the internal link to bibliography, I am not sure what link address should I use. At the moment, I insert this link in the pdf figure "cite.citation_key" But the result is that the hyperlink points to /home/user/cite.citation_key instead of the bibliography. Does anyone know how to achieve this. | 0 |
We were happy before. There was a market next to the school before. I saw a whale before. These are from a grammar book for kids that I'm proofreading, and this part is about "past simple tense". I would like to ask if these sentences are grammatically correct regarding the use of "before." It seems that "before" should be used with perfect tense? Should I make the following changes? Thank you! We were happy then. There was a market next to the school (sometime ago). I saw a whale (sometime ago). | 0 |
We have the adjective "facial" for the noun "face", and I am wondering what the counterpart for the noun "head" is. I could not find it on Google, and ChatGPT told me "cranial" which seems a bit different from what I expected. Thank @Stuart F for the comment! My original thought was to make a joke on myself who can have some kind of "head expressions" (corresponding to "facial expressions") because I am a bit bald. And I am also happy to see that the vocabulary can be different in different contexts! | 0 |
Newton's globe experiment: two globes that share all their features are connected with a rope in an otherwise empty universe. Newton introduced this experiment to show that even though the cases where the globes don't move and where they rotate are not distinguishable relationally (i.e. considering their distance to each other), we can nevertheless distinguish them due to inertial forces that only occur in the rotation case (tension on the rope between the two globes). My question: could Newton also have chosen an example using linear accelerated motion instead of angular accelerated motion? Inertial forces should occur there as well. If not, why does he need circular motion to make his point? | 0 |
I know that "soliton" waves can consist of a crest without a trough. One would expect the reverse to be true as well. However, this Wikipedia excerpt says, So for this nonlinear gravity wave it is the total water depth under the wave crest that determines the speed, with higher waves traveling faster than lower waves. Note that solitary wave solutions only exist for positive values of H, solitary gravity waves of depression do not exist. Is this true, and if so, why? | 0 |
I'm still introducing myself in derivation, antiderivation and integrals, because I haven't studied it in class yet (I will study it next year and derivation in some months), but well, about my question I have seen that integrals and antiderivatives, at least, looks like the same, so, is that true? and also I didn't understand at all why the integration gives you the area, I mean, realize that derivation gives you the value of the slope is easy, but why the antiderivation gives you the area is a bit harder for me to understand, thanks! | 0 |
Alright so I am confused somewhat about Neutron Heavy Nuclei not decaying, or more specifically why it is that Neutron Heavy Nuclei sometimes decay by emitting Neutrons. Someone has already answered why neutron-heavy nuclei decay in general, weak force beta decay basically happens until it can't, but I do not understand why neutron heavy nuclei can, sometimes, emit Neutrons. I am talking about the light elements that have neutron upon neutron upon neutron. Hydrogen Isotopes beyond Tritium decay by Neutron Emission, why? Why doesn't it decay by beta decay? Why do other neutron heavy light elements perform neutron emission? | 0 |
We know that flowing water remains liquid even in the below-zero temperatures (a good example is rivers in arctic regions). Of course water doesn't remain liquid forever if temperature goes down constantly. Also, I know water freezes from surface. But that's for stationary waters like lakes. Not for flowing waters like a dam output which is so fast. I think it depends on a sort of things, like the speed of molecules, the viscosity of water, etc. Can we formulate it to find the answer? Perhaps with such a formula we can find the freezing temperature of other flowing liquids as well. And a minor question: How does the density of flowing water behave in below-zero temperatures? | 0 |
Consider a one dimensional chain of N classical point masses interacting with harmonic neighbor forces (with periodic boundaries for specificity). If the positions and velocities are prepared in a configuration corresponding to a specific oscillation mode, can the energy be transferred to other modes ? Or does the chain oscillate in that prepared mode forever ? Intuitively I do not see a reason why the energy should be transferred to other modes, but I am not sure. However supposing that is the case, does the chain return to that mode if small random disturbance is added at some time ? How is the stability of this mode to perturbations ? | 0 |
I was planning on using whipping boy but it seems that means more like a scapegoat (ie someone who is innocent but made to take the blame for others). Moreover, I want something that means that everyone seems to point to one particular person as the bad example and turn a blind eye to the same behavior in others. The issue is more with reputation or perception from an outside group than guilt per se, but I don't want to suggest that the example person is innocent. The context is history. | 0 |
I would like to calculate the repulsive force between two permanent magnets in a different variations of distance between the two polarity faces. Can the different distances associated to different repulsive forces be related to the magnetic field? Can the magnetic field have a variation when the distance between the magnets change? Can a tesla meter measure the magnetic field in the space between the two magnets? Can the repulsive magnetic flux between two permanent magnets be measured with a tesla meter? Thank you! | 0 |
I was writing a Statement of Purpose letter and I am stuck with this dilemma. Here is what I wrote: I pray that this letter attains your approval. I first used "gains" but my mind instantly switched it to "attains", as the word seems more formal...and then I thought of "obtains", which only got me more confused. All I know is that these words have the same meaning of getting something but I'm still struggling with the context/condition it should be used on. Which one should I use? | 0 |
I found that the definition of coherent phonon: A femtosecond laser pulse can initiate collective, in-phase atomic motions in solids called coherent phonons. My question is: what is the difference between coherent phonons and acoustic phonons? Acoustic phonons also mean the displacement of atoms has the same amplitude, direction and phase. Does it mean atoms move in phase and collectively for acoustic phonons? Thanks in advance. | 0 |
Is there a word that symbolize a status of either unstarted, started or completed ? For example a football match can be either unstarted, started or completed. I would like another word than "status" to indicate those lifecycle adjective, as we have a lot of other "status" in this context. Something like "completionStatus" : but this is not really it, as this is just about completion. I thought about lifecycle but that's too biology oriented. | 0 |
Throwing a small stone on the surface of a calm pond of water creates concentric ripples on the water surface starting from the point of impact and travelling outwards like transverse waves. At the same time the momentum of the sinking stone creates longitudinal underwater pressure waves that propagate outwards with the speed of sound in water. I am interested for an equation that describes the propagation speed relation of these two different types of waves created. Will the surface transverse waves have the same propagation speed with the underwater longitudinal pressure waves and if not how can the propagation speed of each type of wave calculated for water? | 0 |
How do you find the area of the highlighted subsection of a circle? Linked Below. The circle has a known radius from A-O and a trapezoid that lays inside it. The trapezoids longest edges contact the circle circumference at points D and E. All edge lengths of the trapezoid are known. The shortest distance from the center of the circle to the inner most edge of the trapezoid is also known, O-F. I'm trying to design a lid with these dimensions and need to know the area to get the lids weight. The trapezoid portion with the highlighted area will float on top of a fluid. Unfortunately, I don't remember much from my High School geometry class. Thanks for the help in advance. | 0 |
I'm curious about pendulums and their behavior during a solar eclipse. I also wonder about gyroscopes and if their behavior during stellar events has been observed. I wonder about the both of them, and of their relationships to each other. I wonder about Mobius loops and gyroscopes; what if a gyroscope was a Mobius loop in rotation, would it precess in a traditional manner? What if you lined the outer rim of a gyroscope with a plurality of strong magnets, all spinning the same way outwards? What would happen next? I wonder endlessly. | 0 |
Suppose, I have a sample from an unknown distribution. I want to prove/disprove (mathematically!) the following statement: The maximum likelihood (ML) estimator for the (unknown) population mean will always be equal to the sample mean irrespective of the likelihood function. We suppose that, the likelihood function is twice differentiable with respect to its parameters and the mean and variance is finite under the inverse likelihood function (pdf). I believe for symmetric distributions it is straightforward. To maximize the likelihood the center of the mass should be placed at the mean. So, sample mean should be the best estimator to maximize the likelihood of the observed data. But I can not relate to it mathematically. | 0 |
I have a question about contact force and normal force. whenever two bodies are in contact and one body tries to push another body there will be a normal force acting between them. like when we push or pull a body, when we hit a ball by a bat, when we lift a body from ground, like pushing a wall at horizontally or at an angle etc... these all are contact forces does that mean that all contact forces are normal force? | 0 |
Basically something that starts with the substitution principles, definition of an equation, of subtraction and division, axiom of opposites, your usual commutative, associative, distributive axioms, and covers all the way up to the end of high school trigonometry. Dolciani's two volume "Algebra: Structure and Method" was good but I need another similar work. Serge Lang's "Basic Mathematics" wasn't good enough. Reading the first few chapter of abstract algebra books wasn't that helpful as they were too broad in scope. Any other suggestions? | 0 |
Lately I've been approaching problems with conservation of momentum of systems, I was wondering, if I draw the free body diagram, then write the equations and then add them togheter; if momentum is conserved along an axis I will always get that the sum of the forces must be equal to zero in the equations of the dynamic along the axis where momentum is conserved, is that right? | 0 |
Subsets and Splits
No saved queries yet
Save your SQL queries to embed, download, and access them later. Queries will appear here once saved.