Theorem Definition and 1000 Threads

  1. S

    MHB Is Theorem 5.2 in SET THEORY AND LOGIC True or False?

    In the book: SET THEORY AND LOGIC By ROBERT S.STOLL in page 19 the following theorem ,No 5.2 in the book ,is given: If,for all A, AUB=A ,then B=0 IS that true or false If false give a counter example If true give a proof
  2. Lunct

    Why is "super-determinism" a loophole to Bell's theorem?

    So I have often heard it argued that "super-determinism" is a loophole to Bell's theorem, that allows a local hidden variable theory. Bell himself alluded to it in a 1980s BBC interview. But why is this the case? And how is super-determinism different to regular determinism. And the many-world's...
  3. C

    Decrease of Solar radius per year using Virial Theorem

    Hello, I am trying to solve this question: Assume that the Sun's energy production doesn't happen by fusion processes, but is caused by a slow compression and that the radiated energy can be described by the Virial Theorem: $$L_G = - \frac{1}{2} \frac{GM^2}{R^2} \frac{dR}{dt} $$ How much must...
  4. wrobel

    A How Does Noether's Theorem Extend Beyond Conservation in Hamiltonian Systems?

    In Hamiltonian statement the Noether theorem is read as follows. Consider a system with the Hamiltonian function $$H=H(z),\quad z=(p,x),\quad p=(p_1,\ldots,p_m),\quad x=(x^1,\ldots,x^m)$$ and the phase space ##M,\quad z\in M.## Assume that this system has a one parametric group of symmetry...
  5. L

    Proportionality theorem and projectile motion

    So i have this question. If a projectile is fired from a spring loaded system and when it goes pass a chronograph, reads 300FPS and has a mass of 0.12grams. Is there any way to use the proportionality theorem (1/3=x/6 example) to approximate how fast a mass of 0.25grams is when fired from same...
  6. AHSAN MUJTABA

    Electrodynamics and the Poynting theorem

    In my opinion the field momentum is the field's intrinsic momentum which it will give to charges(if any present)...
  7. fluidistic

    Gauss' divergence theorem and thermoelectricity contradiction

    I get a nonsensical result. I am unable to understand where I go wrong. Let's consider a material with a temperature independent Seebeck coefficient, thermal conductivity and electrochemical potential to keep things simple. Let's assume that this material is sandwiched between 2 other materials...
  8. LCSphysicist

    Prove a theorem about a vector space and convex sets

    Summary:: Be the set X of vectors {x1,...,xn} belong to the vector space E. If this set X is convex, prove that all the convex combination of X yet belong to X. Where convex combination are the expression t1*x1 + t2*x2 + ... + tn*xn where t1,...,tn >= 0 and t1 + ... + tn = 1 I tried to suppose...
  9. mertcan

    Linear programming and resolution theorem

    Hi everyone hope you are well, I would like to express what I have done for this question: Proving and employing caratheodory theorem we can say that any point in polyhedron can be expressed as a convex combination of at most n+1 points (where n is the space dimension) in same polyhedron that...
  10. S

    I Is there a theorem that a set of binary swaps can affect any permutation?

    Is there a theorem that states that a set of binary swaps can result in any permutation? For example, the original set (1,2,3,4,5) can have the swap (24) and result in (1,4,3,2,5). is there a set of specific swaps for each net result permutation?
  11. TheGreatDeadOne

    Using the Divergence Theorem on the surface of a sphere

    The integral that I have to solve is as follows: \oint_{s} \frac{1}{|r-r'|}da', \quad\text{ integrating with respect to r '}, integrating with respect to r' Then I apply the divergence theorem, resulting in: \iiint \limits _{v} \nabla \cdot \frac{1}{|r-r'|}dv' =...
  12. J

    I Decomposition per the Fundamental Theorem of Finite Abelian Groups

    According to the book I am using, one can decompose a finite abelian group uniquely as a direct sum of cyclic groups with prime power orders. Uniquely meaning that the structures in the group somehow force you to one particular decomposition for any given group. Unfortunately, the book gives no...
  13. L

    Engineering De Moivre's theorem to express power

    A)Use de moivres therom to express power in simplest polar form Workings Do i need to divde the 60^o by 10 aswell
  14. E

    B Don't understand proof of Bloch theorem

    The potential inside the crystal is periodic ##U(\vec{r} + \vec{R}) = U(\vec{r})## for lattice vectors ##\vec{R} = n_i \vec{a}_i##, ##n_i \in \mathbb{Z}## (where the ##\vec{a}_i## are the crystal basis), and Hamiltonian for an electron in the crystal is ##\hat{H} = \left( -\frac{\hbar^2}{2m}...
  15. andyonassis

    Moment of inertia (Perpendicular axis theorem)

    So i derived the moment of inertia about the axis of symmetry (with height h) and I am confused about the perpendicular axis theorem. The problem ask to find the moment of inertia perpendicular to axis of symmetry So the axis about h, i labelled as z, the two axis that are perpendicular to z, i...
  16. AN630078

    Factor Theorem and Trigonometric Equations Help

    1. The factor theorem states that (x-a) is a factor of f(x) if f(a)=0 Therefore, suppose (x+1) is a factor: f(-1)=3(-1)^3-4(-1)^2-5(-1)+2 f(-1)=0 So, (x+1) is a factor. 3x^3-4x^2-5x+2=(x+1)(3x^2+...) Expand the RHS = 3x^3+3x^2 Leaving a remainder of -7x^2-5x+2 3x^3-4x^2-5x+2=(x+1)(3x^2-7x+...)...
  17. K

    I Finite fields, irreducible polynomial and minimal polynomial theorem

    I thought i understood the theorem below: i) If A is a matrix in ##M_n(k)## and the minimal polynomial of A is irreducible, then ##K = \{p(A): p (x) \in k [x]\}## is a finite field Then this example came up: The polynomial ##q(x) = x^2 + 1## is irreducible over the real numbers and the matrix...
  18. U

    I Equivalence principle and the Uniqueness theorem

    We work with Maxwell's equations in the frequency domain. Let's consider a bounded open domain ## V ## with boundary ## \partial V ##. 1. The equivalence theorem tells me that if the field sources in ## V ## are assigned and if the fields in the points of ## \partial V ## are assigned, then I...
  19. M

    Potential Flow Theory: Circulation and the Kutta-Jukowski Theorem

    Hi, I just had a quick question about conventions in potential flow theory: Question: What is the convention for ## \Gamma ## for the streamline ## \Psi = \frac{\Gamma}{2\pi} ln(\frac{r}{a} ) ## and how can we interpret the Kutta-Jukowski Theorem ## Lift = - \rho U \Gamma ##? Approach: For the...
  20. M

    Divergence Theorem Verification: Surface Integral

    Hi, I just had a quick question about a step in the method of calculating the surface integral and why it is valid. I have already done the divergence step and it yields the correct result. Method: Let us calculate the normal: ## \nabla (z + x^2 + y^2 - 3) = (2x, 2y, 1) ##. Just to double...
  21. cianfa72

    Circuit Theory - about the applicability of the substitution theorem

    Hi, I've a doubt about the applicability of the substitution theorem in circuit theory. Consider the following picture (sorry for the Italian inside it :frown: ) As far I can understand the substitution theorem can be applied to a given one-port element attached to a port (a port consists of...
  22. Haorong Wu

    B When is the parallel axis theorem not appliable?

    Hello, there. A friend asked me a problem last night. Suppose that a system consists of a rod of length ##l## and mass ##m##, and a disk of radius ##R##. The mass of the disk is negligible. Now the system is rotating around an axis in the center of the disk and perpendicular to the plane where...
  23. G

    Constructive Proofs Proof of Correspondence theorem

    Summary:: I'm reading Adkins' book "Algebra. An approach via Module Theory" and I'm trying to prove theorem 3.15 In theorem 3.15 of Adkins' book says: Let ##N \triangleleft G##. The 1-1 correspondence ##H \mapsto H/N## has the property $$H_1 \subseteq H_2 \Longleftrightarrow H_1/N \subseteq...
  24. A

    Understanding the Divergence Theorem

    Good day all my question is the following Is it correct to (after calculation the new field which is the curl of the old one)to use the divergence theroem on the volume shown on that picture? The divergence theorem should be applied on a closed surface , can I consider this as closed? Thanks...
  25. murshid_islam

    B A question about a YouTube video on Thales's Theorem

    Here is the video in question: In the video at 4:23, Michael says, "Now Thales's Theorem tells us that the two other points, where these rays contact the circumference, are diametrically opposed. They are on opposite sides of the circle and a line passing through them will pass through the...
  26. J

    Divergence Theorem Problem Using Multiple Arbitrary Fields

    My main issue with this question is the manipulation of the two arbitrary fields into a single one which can then be substituted into the divergence theorem and worked through to the given algebraic forms. My attempt: $$ ∇(ab) = a∇b + b∇a $$ Subsituting into the Eq. gives $$ \int dS ·...
  27. M

    Stokes' Theorem 'corollary' integral in cylindrical polar coordinates

    Hi, I was just working on a homework problem where the first part is about proving some formula related to Stokes' Theorem. If we have a vector \vec a = U \vec b , where \vec b is a constant vector, then we can get from Stokes' theorem to the following: \iint_S U \vec{dS} = \iiint_V \nabla...
  28. R

    Applying Stokes' Theorem to the part of a Sphere Above a Plane

    I've tried a few ways of solving this, both directly and by using Stokes' Theorem. I may be messing up what the surface is in the first place F= r x (i + j+ k) = (y-z, z-x, x-y) Idea 1: Solve directly. So ∇ x F = (-2,-2,-2). I was unsure on which surface I could use for the normal vector...
  29. E

    B Control volumes and Reynolds transport theorem

    If we consider a system of fixed mass as well as a control volume which is free to move and deform, then Reynolds transport theorem says that for any extensive property ##B_{S}## of that system (e.g. momentum, angular momentum, energy, etc.) then$$\frac{dB_{S}}{dt} = \frac{d}{dt} \int_{CV} \beta...
  30. K

    A Equipartition theorem and Coupled harmonic oscillator system

    Dear all, While simulating a coupled harmonic oscillator system, I encountered some puzzling results which I haven't been able to resolve. I was wondering if there is bug in my simulation or if I am interpreting results incorrectly. 1) In first case, take a simple harmonic oscillator system...
  31. entropy2008

    Cauchy-Riemann Theorem Example in Physics

    I was thinking of the wavefunction in QM but I'm not sure how it's used and when.
  32. LCSphysicist

    Pappus Theorem and Ellipsoid Fig One: Is My Integral Approach Correct?

    fig one: I just want to know if i am right in attack this problem by this integral: *pi Anyway, i saw this solution: In which it cut beta, don't know why. So i don't know.
  33. C

    MHB Implicit function theorem for f(x,y) = x^2+y^2-1

    $f: \mathbb{R^2} \rightarrow \mathbb{R}$, $f(x,y) = x^2+y^2-1$ $X:= f^{-1} (\{0\})=\{(x,y) \in \mathbb{R^2} | f(x,y)=0\}$ 1. Show that $f$ is continuous differentiable. 2. For which $(x,y) \in \mathbb{R^2}$ is the implicit function theorem usable to express $y$ under the condition $f(x,y)=0$...
  34. S

    I Bell's Theorem - why product of (2)spins can be +1 (Griffith's text)

    Hello, Within Griffith's text - chap 12 section 12.2 page 423 - this is a brief summary of Bell's Theorem and description of Bell's 1964 work. There is a table on page 423 showing the spin of the electron and positron (from pi meson decay) - these would be in the singlet state, one would be...
  35. D

    Evaluate integral using Green Theorem

    I got stuck here, how to integrate e^(y^2), I searched but it's something like error function
  36. bryanso

    Understanding Feynman's Discussion of the Parallel Axis Theorem

    https://www.feynmanlectures.caltech.edu/I_19.html "Suppose we have an object, and we want to find its moment of inertia around some axis. That means we want the inertia needed to carry it by rotation about that axis. Now if we support the object on pivots at the center of mass, so that the...
  37. PeroK

    How Does Wick's Theorem Apply to Time-Independent Bose Operators?

    This is problem 18.3 from QFT for the gifted amateur. I must admit I'm struggling to interpret what this question is asking. Chapter 18 has applied Wick's theorem to calculate vacuum expectation values etc. But, there is nothing to suggest how it applies to a product of operators. Does the...
  38. H

    A Lovelock Theorem & FRW Domain Wall Cosmological Model in f(G) Theory

    I have worked out a FRW domain wall cosmological model in f(G) theory of gravitation. I have received one comment that this model violets Lovelock theorem. Are there any constraints to cut massive gravitation modes with higher derivative models in gravitational wave GW170817?.
  39. jisbon

    Engineering Finding the maximum power delivered using Thevenin's theorem

    Using mesh analysis, my simultaneous equations seem to be wrong and I can't figure out why. Any stuff that I should take note of? Attempt:
  40. DaveC426913

    Newton's Shell Theorem and charge

    I've been discussing Newton's Shell Theorem re: gravity with someone, and thought of the analogy to charge. 1. I think the net effect on a negative charge inside a hollow sphere of positive charge will be zero. i.e. No net attraction. Yes? 2. But what would happen to the magnetic field if the...
  41. parshyaa

    What is the Limiting Value of Integral in Newton's Shell Theorem for r=R?

    First i tried proving Newton shell theorem directly for r=R and solved the integral as above but still got the wrong solution. Here i tried using general case: Here r' is the distance of a small ring from the point particle of mass m So my doubt is when we take r=R and then evaluate this...
  42. benorin

    The Bohr-Mollerup Theorem [Fixed tech difficulties, thx]

    Now I realize this is not the simplest way to do this problem, I get that, so please don't answer me with the "Try doing it this way..." posts. I would like to see if we can please make this solution come to life. The first kink in the proof is the functional equations, I know it should work...
  43. F

    I Asymmetry in Stokes' theorem & Gauss' theorem

    Stokes theorem relates a closed line integral to surface integrals on any arbitrary surface bounded by the same curve. Gauss theorem relates a closed surface integral to the volume integral within a unique volume bounded by the same surface. What causes this asymmetry in these 2 theorems, in the...
  44. M

    How Does Parseval's Theorem Apply to Noise Amplitude Calculations?

    Before: ##\int_\infty ^\infty {\left| F_i(u) \right|}^2 du=\int_0 ^{40} a^2 du=40 a^2## Therefore: ##a^2= \frac{1}{40}\int_\infty ^\infty {\left| F_i(u) \right|}^2 du## After: ##\int_\infty ^\infty {\left| F_f(u) \right|}^2 du=\int_0 ^{10} a^2 du=10 a^2## Therefore: ##a^2=...
  45. Pouyan

    Clausius' Theorem: Solving the Mystery of T ∑(dQi/Ti) =< 0

    I see this in my book but there is something I don't get! If we consider a Carnot cycle where heat Qh enters and heat Ql leaves, We know Qh/Ql=Th/Tl And we define ΔQ_rev then : ∑(ΔQ_rev/T) = (Qh/Th) - (Ql/Tl) =0 I insert an image: Which shows the heat dQi entering the reservoir at Ti from a...
  46. F

    I Any surface bounded by the same curve in Stokes' theorem

    In Stokes' theorem, the closed line integral of f=the surface integral of curl f on ANY surface bounded by the same curve. But in Gauss' theorem, the surface integral of f on a surface=the volume integral of div f on a unique volume bounded by the surface. A surface can only enclose 1 volume...
  47. S

    Basic Proportionality Theorem (Thales Theorem)

    According to Basic proportionalit theorem if a line is parallel to a side of a triangle which intersects the other sides into two distinct points, then the line divides those sides proportionaly. I can't figure a way out how to prove it. Here is an attempt. we know that AE/EB = AD/DC.
  48. F

    I Vector field and Helmholtz Theorem

    Hello, A generic vector field ##\bf {F} (r)## is fully specified over a finite region of space once we know both its divergence and the curl: $$\nabla \times \bf{F}= A$$ $$\nabla \cdot \bf{F}= B$$ where ##B## is a scalar field and ##\bf{A}## is a divergence free vector field. The divergence...
  49. Math Amateur

    I Closure & Interior as Dual Notions .... Proving Willard Theorem 3.11 ...

    I am reading Stephen Willard: General Topology ... ... and am studying Chapter 2: Topological Spaces and am currently focused on Section 3: Fundamental Concepts ... ... I need help in order to prove Theorem 3.11 Part 1-a using the duality relations between closure and interior ... ..The...
  50. binis

    B Is the Euclidean postulate a theorem?

    Consider a point A outside of a line α. Α and α define a plane.Let us suppose that more than one lines parallels to α are passing through A. Then these lines are also parallels to each other; wrong because they all have common point A.
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