darklight03/StackMIAsub huggingface dataset:
I have recently moved to an institution run by the British government where staff use the term "indent" as a noun to refer to an inventory exercise done to work out what they need to buy. This is consistent with several dictionaries, such as Merriam Webster: chiefly British a : an official requisition b : a purchase order for goods especially when sent from a foreign country Does anybody know where this usage comes from?
I was reading a book, the author described the scenery of a certain place, and then said: "You're hooked for life." The search engine told me it means, you have been fascinated by this scenery all your life, "for life" represents the duration of the action of fascination. My questions are: Can this sentence only be used after the previous sentence describes the charm of something? If I want to express people's obsession with life itself, can I use "hooked on life"? Your reply will be greatly appreciated!
I've recently read about a subject field called "Boolean differential calculus", which discusses changes of Boolean variables and functions. This subject defines the derivative of a Boolean function, its minimum/maximum, etc. While the field sounds very interesting, I couldn't find much about its applications. I found a book by Steinbach and Posthoff called "Boolean Differential Calculus" which describes applications, but it's under a paywall. For any of you familiar with the subject, what are some interesting applications that can be done with it? I would also be interested in sources that are open-access. Thank you in advance!
I don't have any physics background aside from intro physics so apologies if my question sounds very shallow. If lens power is based on focal length, but our eyes adjust its focal length based on the distance of the object we are observing, how do we know that our lens prescription is correct for all distances? Most eye tests I have done involve focusing on objects at a far distance. If our lens prescription is based on focal length when we focus on objects at a far distance, is it incorrect to be using this prescription when doing near distance work?
I'm curious, if based on what we know with Newton's law, can we determine if a random planet, knowing it's mass and gravitational pull, can hold a moon in it's orbit. Or to phrase it another way, is there a gravitational force "range" in universe where if a planet has a force less than that range, a moon won't stay in orbit and just escapes and if the planet has a force more than that range, the moon is pulled into the planet.
Let's say we have an undirected graph G, where V = number of nodes and E = number of edges. In this graph, there are vertices with odd degrees as well as even degrees, but I have to transform the graph to one with only even degree nodes and I can do that by removing some edges. How do we find the number of ways to remove the edges so that there are no nodes with odd degrees left (this could also mean removing all edges altogether)? Thanks a lot!
The elongation of light waves occurs not because galaxies are moving away from each other, but because light waves are stretching along with the fabric of expanding space (cosmological redshift). Although the Milky Way is held together by gravity, space expansion occurs everywhere, including within the Milky Way. Since space expansion occurs in the Milky Way and light stretches due to space expansion, why don't we observe cosmological redshift within the Milky Way?
In the derivation of potential energy of two-point charge system, we define the potential energy of the system as the work done in giving both charges to their present configuration, and while doing the derivation, we assume the work done in bringing the first charge to its desired configuration to be zero, but I think it shouldn't be like that. Why is the force = qE acting on the first charge due to the second charge being ignored while calculating the work done in bringing the first charge to the desired configuration?
How can I learn General Relativity? Am a undergrad student, who happens to be interested in general relativity. I want to learn it by heart. What are the prerequisites for it? As a fresher who just got into undergrad, what resources are best for me? Feel free to suggest any YouTube playlist which can help me understand the math of relativity and any book that teaches me from scratch presuming I know nothing.
I'm doing 'longitudinal' qualitative research, and to avoid continually being accused of assuming that I will find change, I need a term that covers both change and stasis - so I can say that I'm looking for instances of [change-or-stasis] in particular areas of experience over a particular period of time. One researcher gets round this by saying that stasis is a type of change, but I'm not sure that works. Any thoughts gratefully received!
I have been curious about intuitionistic logic for some time and I want to know about it and I have a question, the law of the excluded middle and double negation elimination seem completely logical to me and I think they are always correct. But intuitionistic logic does not accept these two laws. What is the cause of this? Are there really propositions in mathematics for which these two principles do not hold? If so, please give examples of propositions that are examined in intuitionistic logic and the law of the excluded middle and double negation elimination does not work in them.
I have been trying to get my head around this proof, but i just don't manage to do so. I am ok with the first two lines, it is just the definition. But on the next line, how is Cauchy-Schwartz inequality exaclty applied? And on the next line, I also don't understand how is Taylor's Theorem used. Update: I just managed to figure out the usage of Cauchy-Schwartz. But I still don't understand how Taylor's Theorem was used.
The Nyquist limit for interpolation by trig functions states that one must give at least two data points per wavelength, because data just above and just below this "folding frequency" cannot be distinguished. I am currently playing with Hermite interpolation, providing the first few derivatives as well as the function values, and find that the Nyquist limit no longer applies. This cannot be a new observation, but I don't find anything about it online. Maybe I have not got the appropriate vocabulary?
I've been reading a lot of various classic literature, and at times there is the sort of casual misogyny or racism that was commonplace and (within certain cultures) the social norm at that time. Such things are no longer so commonplace and generally aren't tolerated. I wish to have a concise adjective or noun to describe those things when discussing them that isn't so oblique and timid as "outmoded" or "archaic", but I cannot recall one nor find it with my (perhaps feeble) attempts to search for it online. Has anyone come across such a word? If not, I'm open to a suggested synthesized word or a potential loanword that might one day make it into a dictionary if we use it enough.
I wonder how can I constuct a sphere inscribed in a tetrahedron using GeoGebra? I've thought I can construct it using the intersection of three planes bisecting angles between some pairs of faces in a tetrahedron, but when I contructed it, it didn't seem to work. Is this construction valid and I made some mistake while constructing the planes, or is it not a proper construction? If it is the latter, what is the proper way?
If amber and cloth are rubbed together, it is known that some electrons are transfered from cloth to amber. In this case, cloth acquires a positive charge and amber a negative charge. If these two have opposite charge, shouldn't there be electrostatic force between these two ? So, the next time you rub these two items, shouldn't the electrons be transferred from amber to cloth?
A solid sphere rolls without slipping up and then down an incline. Why does the static friction force point up the incline both when the object is rolling up and also when it's rolling down? I know it's necessary for the force to point up when the object is rolling up, because then it's the only source of torque on the object, and for the object to roll back down the incline, there must be a torque which acts in the opposite direction of the initial angular velocity. However, I don't understand why this is the case. Why does the force need to point up the incline to create the necessary torque, particularly when the object is rolling back down the ramp?
"Mill" is usually used to describe the process of making flour (grinding), to describe a wind or water mill, or a factory. Since the process of milling or grinding consists of making small pieces or powder out of objects, I was wondering if the word "mill" can be used figuratively as in kill, destroy, obliterate or tear to pieces? For instance, in the context of a competitive computer game, would it make sense to say something like "I was milled" as in "I was obliterated" when losing a game as a kind of way to add a bit of color to the expression?
According to the S-B Law, an area of mass will radiate out heat energy equal to the fourth power of its temperature in degrees Kelvin. If energy cannot be created nor destroyed, how can a body give off more heat than it receives? I understand how a magician seems to make a pigeon appear from nowhere, but I can't understand how so much more heat is being radiated out than was absorbed by the mass. How is this possible?
I'm going to take an introductory class on dynamical systems at the level of Guckenheimer & Holmes, or Arnold's ODEs book, but I don't have any topology background. I know analysis at the level of Stein's Fourier and Complex analysis, but have not had exposure to full-blown measure theory or manifolds. Is there a book that covers basic point-set topology in an accessible manner but perhaps without unneeded generality? Thanks!
I'm reading through the paper "Lagrangian Intersection and the Cauchy Problem" by Melrose and Uhlmann, and I'm having trouble with the definition of intersecting pair of Lagrangian manifolds. I am aware of the definition of conic Lagrangian manifold, but what is a conic Lagrangian manifold with boundary? Do we require the boundary to be isotropic or is it that if a conic Lagrangian submanifold has boundary then the boundary is always isotropic, or do we just define it to be such that the interior is a conic Lagrangian submanifold?
I have a circle and a line with the length of its circumference. One end of the line is attached to a point on the circle circumference, forming the shape of the lowercase 'b'. Now, the line begins to wrap the circle clockwise, until it completes one revolution around the circle, where there's no more "line". What is the path created by the free end of the line?
I've always thought of a transformation as "the movement of a mathematical object through space", but I found this definition that seems to be better: "An operation that changes the status of a (mathematical) object to another state." Does anyone have a better definition that works for both dilations and isometries and also with more advanced math like linear transformations? Or, what would be the best way to combine these definitions? Is the "space" part important?
The proof is quite obvious but how do you write it down nicely? I have this problem a lot with graph theory proofs where I don't know how to write them down so that they are rigorous enough. The proof itself would go something like this: Let C be a cycle in G.If we remove the edge e = {u, v} from C then C becomes a path between u and v. C is still connected so G is also still connected.
I am looking for a word that describes advice that is too obvious to be helpful. Imagine asking for advice, and someone responds with simply saying to "do what is desirable" or "avoid what is undesirable" in the context of the advice. For example, if you asked someone for exam prep advice, and they simply said "don't fail", or if you asked for advice in marathon preparation and someone said "don't get tired". One might use the adjective as follows: "Please spare your ____ advice"
I'm not a physicist so I'm asking you guys. We have been told that a device ("medical"...) uses a laser to irradiate a biological body (human, animal,...). The laser should apparently penetrates through metal and concrete (without destroying it). Can a laser penetrate through metal, concrete, ... without destroying the material? I don't believe that. After all, laser is light and light does not penetrate through steel or concrete. Except it's super thin, so the density would not be enough. Am I right with that? Thanks!
I've only started my own studies on grammar recently and as I was reading CoGEL by Randolph Quirk, I came across this category called 'Catenative verb constructions'. According to the analysis used in the book, catenative verb constructions cannot be interpreted as verbs followed by a nonfinite clause acting as a direct or prepositional object. However, 'manage to' is also included yet when I look up the dictionary, 'manage' can be transitive even when used with the meaning 'to succeed in doing something, especially something difficult' like in these examples: In spite of his disappointment, he managed a weak smile. I don't know exactly how we'll manage it, but we will, somehow. Shouldn't 'manage to' be listed elsewhere then ? Or am I misinterpreting something ?
I am trying to use the Poisson process for BLE(Blueetooth Low Energy) neighbor discovery. In this context, there are two devices called Advertiser and Scanner. The advertiser and scanner emit and listen to beacons in a duty-cycled fashion. This leads to longer discovery latency sometimes and I want to use the poisson process for the scanning and advertising patterns and prove the discovery is going to happen. Basically I want to merge two poisson processes and make sure there are two events within a small interval delta.
I recently used a shear interferometer for aligning two lenses in an optical setup (a Galilean beam expander to be precise). I was able to align the lenses such that the vertical stripes were perfectly vertical (i.e. the beam is collimated). But I noticed that the image showed slight fanning: With fanning I mean that the stripes seem to be expanding when going to the right. Does anyone know which type of aberration causes this? I'm using this shear interferometer:
Is it possible to find the highest "noise" value along a line segment defined by two endpoints within a Simplex (or Perlin) function by using an equation? The reason I ask is to avoid expensive ray marching. It's fine if there are multiple points along the segment with the maximum value. It would be preferred if it could work with multiple octaves of Fractional Brownian Motion as well. I'm fairly certain it's possible but it might be too difficult to derive. Corresponding code for the simplex (snoise) function can be found here. I've added a rudimentary image to show what I'm trying to do here :P
I have a background in acoustics and do more and more of quantum mechanics. I wonder why don't we use more often the bra-ket notation in acoustics and vibrations like in quantum mechanics? In modal analysis, we deal everyday with Hilbert spaces, inner products and linear algebra so I think that it would make sens to use the notation in the same manner. Is it because the notion of state vector is less important in those contexts?
Reading through wikipedia's page on international law, I noticed that there is never a definite article "the" before the phrase. It is a set of rules, norms, and standards generally recognised as binding between states, so it should be quite a definitive thing, right? So why is there no definite article? Compare: the constitution, the second amendment, the Bill of Rights, the Defense of Marriage Act, the Non-Proliferation Treaty.
Is there more than one definition to "polarization" in the context of waves? In some cases, I've seen the term "direction of polarization", which I presume it refers to the direction of oscillation. In other context, I see this word use as a process of turning unpolarized waves into polarized waves. Also, there are times whereby people say that "polarization only occurs in transverse waves", which implies that polarization is a property/phenomenon of transverse wave. So is polarization a property, a process, an adjective to describe the direction of oscillation, or is it all of the above? Is there any other definition of polarization I'm missing here in the context of waves?
I am studying about fibre bundles. If a fibre bundle is locally trivial then I understand the fibres are locally isomorphic. Also I understand that any compact Hausdorff base space cannot have a disjoint finite open cover for if I have a disjoint finite open cover then base space is disconnected. My question is, if my base space is connected, then are all the fibres isomorphic to each other?
I have been watching videos of WIMP's and have a simple question.. The larger the particles, the shorter their lifetime. A top quark is so massive that it cannot form a "stable" bond with any other particle to form a meson or baryon. If WIMPS are too massive to make in a particle accelerator, how can they still be around today to affect gravity of galaxies? Wouldn't they have decayed by now into things we could see or detect?
I have an enclosure mounted to the chassis of a vehicle. There are multiple points where the enclosure is fastened to the chassis as well as areas where it rests on the chassis without being fastened. Is there any point in putting vibration pads on the areas where the enclosure rests on the chassis? Logically I feel like anything fastened rigidly to the chassis would vibrate the same as the chassis.
Could anyone help me to understand the difference between the usage for and to in the below sentences. They will be more interested in the struggles of the downtrodden, in those who are fighting to obtain the title deeds for respectable humanity. They will be more interested in the struggles of the downtrodden, in those who are fighting to obtain the title deeds to respectable humanity. Ideally, both the sentences are correct, however the preposition for is mostly followed by a noun whereas the preposition To is mostly followed by verbs. So, why is "To" correct in the second sentence in comparison with the first sentence?
On plotting the angle of deviation vs the angle of incidence for a prism, we find that the graph dips only at one point. It is this result that is later used to prove that for minimum deviation to occur in a prism, the angle of incidence must be equal to the angle of emergence. But why exactly does the graph have only one minima? Are there any mathematical or physical reasons behind this phenomenon, or is it a purely empirical result?
In his famous hit Working Class Man, Jimmy Barnes sings: He believes in God and Elvis He gets out when he can He did his time in Vietnam Still mad at Uncle Sam I can't make sense of the second line. What could it mean? What does he get out of? I thought that the line in question might be some idiom or slang known among workers, so I looked in dictionaries, but found no idiom or slang that would fit the context. Maybe it's something obvious to native speakers, but I am not one. I humbly hope that users of this SE can shed light on this mystery.
I am a beginner to Lie groups and Lie algebra. Recently, I learnt that the dimension of the Lie algebra generated by a Lie group is the same as that of the Lie group. I have known for a long time that the space of vector fields on a manifold (even when not considered a Lie group), forms a Lie algebra. Is there any conclusion that can be made about the dimension of this Lie algebra? It seems to me that the Lie algebra generated a Lie Group (space of left-invariant vector fields) is the subalgebra of the Lie algebra generated by the underlying manifold (space of all vector fields), so their dimensions should not be the same. Any enlightenment is greatly appreciated!
While scrolling through an online document, I came across the statement, "If charges carried by the black hole are large, the curvature at the horizon is small." How is this so? I tried to think of an answer to this. My thinking goes this way: I know curvature is related to mass. If an object is more massive, it bends the spacetime fabric more, producing large curvature. So curvature small means mass small. So how does a large charge mean a small mass for a black hole? What is the relationship between the charge and mass of a black hole?
Is there, or has there ever been, an unambiguous word for "the leftmost extreme" or "the rightmost extreme"? Such words exist for the other two dimensions. Imagine you are floating in a cube in space. You can go up until you hit the top. You can go down until you hit the bottom. You can go forward until you hit the front. You can go backward until you hit the (back/rear). You can go left until you hit the _______? You can go right until you hit the _______?
In an acute-angled triangle ABC, let us denote H as its orthocenter and I as its incenter. Let D be the perpendicular projection of I on the line BC, and E be the image of point A in symmetry with center I. Furthermore, F is the perpendicular projection of the point H on the line ED. Prove that the points B, H, F, C lie on a circle. I think the idea here is the circumcircle BHC is the reflection of circumcircle ABC respect to BC. But I don't know how to proceed, can anybody help?
So, the uncertainty principle states that one can not measure momentum and position with accuracy simultaneously. However, we know from relativity that simultaneously is something frame dependent in nature, so how can we reconcile these two in relativistic quantum mechanics or even QFT? I know that in QFT we define observables in different points in spacetime such that their Lie bracket is zero, but I'm not really sure how to go from this to an answer.
I noticed that whenever I bunch up aluminum foil (into a ball), it becomes extremely hard to compress. If I use another piece of the same amount of aluminum foil, and keep folding it in, I arrive at a much smaller volume. It is full of air and much lighter than the same shape of solid aluminum, though, it is still extremely hard to compress. Question: Why does bunched up aluminum foil become so extremely hard to compress?
I am a graduate student in mathematics studying algebraic logic. For quite some time now, I have been meaning to study physics -- it turns out that some ideas in foundations of mathematics have found promising applications in theoretical physics (topos quantum theory and quantum logic come to mind). I want to get a somewhat rigorous picture of classical and quantum mechanics, so that I can contextualize some of the things I will be reading later on. Is there a good resource that I can use for this? I would prefer to read something that has a careful development of ideas starting with classical mechanics, eventually culminating in a broad formulation of quantum mechanics. All suggestions are welcome!
I came across some interesting dialogue in a tense scene in a novel, Salvation Lost by Peter F Hamilton: "We'll know exactly what the other [people] are seeing and doing." "Doing and seeing," "What?" "Better grammar." "Jesus, man; keep it relevant" Though this is intended as comic relief, it has me wondering if there is any reason why "doing and seeing" is preferable to the reverse. Is there any actual guideline/grammar or does it just sound better to have the more active verb first?
We recently attended a concert in a protestant church in England that was advertised as "free admission with retiring donations". The concert was indeed free with a voluntary (optional) donation. What is the meaning of retiring in this context? Googling without quotes gives results for people retiring from work, which is obviously not meant here, and googling with quotes returned similar events being advertised as such.