Equivalence Definition and 747 Threads

In mathematics, an equivalence relation is a binary relation that is reflexive, symmetric and transitive. The relation "is equal to" is the canonical example of an equivalence relation.
Each equivalence relation provides a partition of the underlying set into disjoint equivalence classes. Two elements of the given set are equivalent to each other, if and only if they belong to the same equivalence class.

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  1. Z

    Questions about Equivalence principle & Einstein Elevator?

    Einstein inoculated general relativity with the help of equivalence principle and space elevator as shown in the following link http://www.astronomynotes.com/relativity/s3.htm QUESTIONS 1- What is the direction of weight [force] of a person standing on the floor of aforementioned...
  2. F

    Do Intervals [2,3] and [2,5] in Real Numbers Share the Same Cardinality?

    Hi - I've got the following question but can't find any concrete information in my books on how to answer it and I'm slightly confused: {x ε R : 2≤x≤3 } and {x ε R : 2≤x≤5 } Do they have the same cardinality? My understanding of this is if you can find a mapping that satisifies a bijection...
  3. F

    Equivalence relation and equivalence class

    i have two relations given to me which are both defined on the integers Z by relation 1: x~y if 3x^2 -y^2 is divisibale by 2 and relation 2: x~y if 3x^2 -y^2 ≥0 I have used three properties to figure out that relation 1 is eqivalence relation as it stands for all three properties i.e...
  4. J

    Mass in MeV/c2 of a particle with a mass of 4.032u

    Homework Statement A particle has a mass of 4.032u. What is its mass in MeV/c2 Homework Equations The Attempt at a Solution 4.032u = 4.032 * 1.66*10-27 = 6.69*10-27 kg Energy equivalent, E = mc2: = (6.69*10-27)*(3*108)2 = 6.02 *10-10J J→eV (divide by 1.6∗10-19) )=3.76∗109...
  5. J

    Hi all,Let λ>0 and define an equivalence relation on

    Hi all, Let λ>0 and define an equivalence relation on ℝn-{0} by (x~y) \Leftrightarrow (there is an s\inZ such that λsx=y) I would like to know what the quotient space ℝn-{0}/~ looks like. I know that it is a set of equivalence classes. To understand it better I wanted to see how it...
  6. M

    Isotropy/Homogeneity of Spacetime and Inertial Frame Equivalence

    So this is problem 11.1 out of Jackson Electrodynamics: Two equivalent intertial frames K and K' are such that K' moves in the positive x direction with speed v as seen from K. The spatial coordinate axes in K' are parallel to those in K and the two origins are coincident at times t=t'=0. (a)...
  7. S

    Equivalence Relation on ℝ: xRy if x≥y | Symmetry and Transitivity Explained

    Homework Statement Determine whether the given relation is an equivalence relation on the set. Describe the partition arising from each equivalence relation: xRy in ℝ if x≥y Homework Equations Reflexive: for all x in X, x~x Symmetric: for all x,y in X, if x~y, then y~x Transitive...
  8. B

    Trouble proving equivalence at limit

    Homework Statement I'm trying to prove that Electric field away from a line segment of charge, is equivalent to the field away from a point charge, provided I observe from far enough. Homework Equations Ignoring all the constants: potential_line = log( (sqrt(r^2 + a^2) + a) /...
  9. E

    Equivalence of p-norms in [itex]C^{0}_{p}[a,b][/itex]

    Homework Statement Let 1\leq s<r<\infty. For what pairs s,r the norms \left\|\cdot\right\|_{s},\left\|\cdot\right\|_{r} are equivalent? Homework Equations I have already proven that \left\|\cdot\right\|_{s}\leq (b-a)^{\frac{r-s}{rs}}\left\|\cdot\right\|_{r} and that...
  10. C

    HELP: Equivalence of NFA's with plugin DFA's

    URGENT HELP: Equivalence of NFA's with plugin DFA's Homework Statement Hello guys! I have been thinking about this problem for weeks and I'm still not sure if the problem is decidable or not. Basically it asks there are NFA's with states that can be substituted to DFA's. Given two such NFA's...
  11. B

    A bit of trouble with Thevenin equivalence with dependent sources

    This really isn't one specific problem per se as it is more of a conceptual issue, so I apologize for breaking away from the given format. I've worked through three problems involving a circuit where a thevenin equivalence circuit is required between two points, and all sources are dependent...
  12. K

    Norm equivalence between Sobolev space and L_2

    Hello! I've found this paper, wherein page 33 states that the reverse Poincaré inequality gives \forall v \in H^1_0(\Omega) , \|v\|_{L^2(\Omega)} \leq C(\Omega) \|\nabla v\|_{L^2(\Omega)} This I can follow - it gives a norm equivalence between the norm of a vector and the gradient of its...
  13. D

    Mass energy equivalence in a bagttery and an animal

    A charged battery should have a mass a little greater than a depleted battery. Surely that is measurable. So does a live person have greater mass than his or her dead equivalent? Surely that is a 2nd law of thermodynamics that would be revealing. Or is the entropy of life so small that it is...
  14. Z

    Binomial identities,combinatorial, equivalence

    NOte this is not a homework nor related to any course nor any test problem etc. - entirely my own interest and study. Re\: text by Biedenharn and Louck "Angular momentum in Q.Physics" . I derive an expression for the norm squared wrt a certain expression in Boson calculus. You don't really...
  15. R

    Proving an equivalence concerning sequences

    given closed subsets, A and B, of R^d with A bounded prove the equivalence of: 1) There exists a pair of sequences x_n in A and y_n in B such that |x_n - y_n| -> 0 as n -> infinity 2) A intersection B is non empty. I have attempted this question but am a bit stuck on proving 1 implies 2...
  16. T

    Proving an equivalence relation using inverse functions

    Homework Statement Let f : A → B be a function and let Γ ⊂ B × B be an equivalence relation on B. Prove that the set (f × f)^-1 (Γ) ⊂ A × A (this can be described as {(a, a′) ∈ A × A|(f(a), f(a′)) ∈ Γ}) is an equivalence relation on A.Homework Equations The Attempt at a Solution Let...
  17. Z

    Redshift and Weak equivalence principle

    Firstly: Does anyone know at our current level of technology what "small enough not to detect tidal forces" equates to? Near the surface of the earth(as it probably depends on the amount of curvature of space). Secondly: Does anyone know at out current level of technology what the minimum...
  18. T

    Help with proving Biconditional equivalence

    show that P \leftrightarrow Q is equal to (P\wedgeQ) \vee (\negP \wedge\negQ) (P→Q) \wedge (Q→P) (\negP\veeQ) \wedge (\negQ\veeP) [\neg(P\wedge\negQ)\wedge\neg(Q\wedge\negP)] \neg[(P\wedge\negQ)\vee(Q\wedge\negP)] I don't know which law to use from this point on to prove the...
  19. R

    Proofs Question: Equivalence Relation and Classes

    Homework Statement Define a relation ~ on ℝ by a~b if and only if a-b∈Q. i) Show that ~ is an equivalence relation. ii) Show that [a]+=[a+b] is a well-defined addition on the set of equivalence classes. Homework Equations Q represents the set of rational numbers. An Equivalence...
  20. F

    Understanding Exactness & Path Independence: Geometric Intuition

    Hi friends, sorry that i have posted so many threads recently regarding complex analysis. i am trying hard to understand as much as possible.anyway i was wondering if anyone had any good geometric interpretation for the equivalence between a differential being exact and it being path...
  21. F

    What is the Induced Equivalence Class for (2, 3) in Relation Υ?

    (x1, y1)Υ(x2, y2) ⇔ x1 × y2 = x2 × y1 for all x1, x2 ∈ Z and y1, y2 ∈ Z+ have been shown to be an equivalence relation in tutorial. Specify the equivalence class [(2; 3)] as induced by Υ. i don't understand what it means by 'Specify the equivalence class [(2; 3)] as induced by Υ.'...
  22. T

    Products of function equivalence classes

    Homework Statement If f ∈ C(R) with f(0) ≠ 0, show that there exisits a g ∈ C(R) such that [fg] = [1], where [1] denotes the equivalence class containing the constant function 1. Homework Equations The Attempt at a Solution Let f ∈ C(R) such that f:R → R is defined as f(x) = 1/x...
  23. T

    Equivalence relations and addition

    Homework Statement prove that if a~a' then a+b ~ a' + b Homework Equations The Attempt at a Solution I can prove that if a=a' then a+b = a' + b but how can I apply this to any equivalence relation
  24. T

    Identifying equivalence classes with the unit circle

    Homework Statement Define a relation on R as follows. For a,b ∈ R, a ∼ b if a−b ∈ Z. Prove that this is an equivalence relation. Can you identify the set of equivalence classes with the unit circle in a natural way? Homework Equations The Attempt at a Solution I have already proven that this...
  25. Z

    Is the Riemann Hypothesis Equivalent to S=2Z?

    let be the function \sum_{\rho} (\rho )^{-1} =Z and let be the sum S= \sum_{\gamma}\frac{1}{1/4+ \gamma ^{2}} here 'gamma' runs over the imaginary part of the Riemann Zeros then is the Riemann Hypothesis equivalent to the assertion that S=2Z ??
  26. C

    Prove a set X is union of disjoint equivalence classes

    Homework Statement Prove: If E1, · · · , Ek are the disjoint equivalence classes determined by an equivalence relation R over a set X, then (a) X = union of disjoint equivalence classes Ej (b) R = union of disjoint (Ej x Ej) Homework Equations R is a subset of X x X The Attempt at a Solution...
  27. C

    Prove Relationship between Equivalence Relations and Equivalence Classes

    I'm not sure if I did these 2 questions correctly, so would someone please check my work for any missing ideas or errors? Question 1: Homework Statement Prove: For every x belongs to X, TR∩S(x) = TR(x) ∩ TS(x) Homework Equations The Attempt at a Solution TR(x) = {x belongs to X such that...
  28. A

    Showing the equivalence of two integrals

    Homework Statement Show for the z-component of the curl of a vector function that the integral off this over an infinitesimal rectangle in the x-y plane is equal to the contour integral of the original vector function around the perimeter. Homework Equations Short of explaining how to...
  29. C

    Equivalence Relation, prove dom(R) = range(R) = X

    Homework Statement Given: R is an equivalence relation over a nonempty set X Prove: dom(R) = X and range(R) = XHomework EquationsThe Attempt at a Solution I have the following thoughts: About the given: Since R is an equivalence relation over X by hypothesis, R satisfies: Reflexivity: <x,x>...
  30. C

    Prove an Equivalence Relation R over N x N

    Homework Statement Given: A relation R over N x N ((x,y), (u,v)) belongs to R. i.e (x, y) ~ (u,v) If max(x,y) = max(u,v), given that max(x,y) = x if x >= y = y if x < y Prove that R is an equivalence relationHomework Equations I know that to prove an equivalence...
  31. S

    And yes, the existential quantifiers make it much easier to solve.

    Homework Statement Suppose R and S are relations on a set A, and S is an equivalence relation. We will say that R is compatible with S if for all w,x,y,z ∈ A, if (w,y) ∈ S and (x,z) ∈ S, then (w,x) ∈ R iff (y,z) ∈ R. Prove that if R is compatible with S, then there is a unique relation T...
  32. S

    Mass-energy equivalence and how it relates to the content of the universe

    I've always been interested in Physics so have finally decided to do a Physics degree. I've been reading various things to help prepare myself and have just been reading about the laws of thermodynamics and mass-energy equivalence. As I'm reading through different articles about these subjects...
  33. S

    Is there exactly one Y ∈ [X]R such that Y ∩ B = {}?

    Homework Statement Suppose B ⊆ A and define a relation R on P(A) as follows: R = {(X,Y) ∈ P(A) x P(A) | (X∆Y) ⊆ B} a) Show that R is an equivalence relation on P(A). b) Prove that for every X ∈ P(A) there is exactly one Y ∈ [X]R such that Y ∩ B = { }. *P(A) is the powerset of A...
  34. A

    Fine Topology on [0,1]: Equivalence to Euclidean Topology?

    Can anyone please help me with this because I'm really getting confused. Thanks! In R, we know that fine topology is equivalent to the Euclidean topology as convex functions are continuous. Now if instead of R we consider a subset of it say [0,1], the fine topology induced on [0,1] would...
  35. G

    Are the following Relations Equivalence Relations?

    Homework Statement Decide if the following are Equivalence relations and if so describe their classes i) a\equiv b if 2 divides a^2+b^2 ii) a\equiv b if 2b\geq a Homework Equations The Attempt at a Solution ii) isn't an equivalence relation. it is reflexive but not...
  36. G

    Equivalence Relations on Z - Are There Infinite Equivalence Classes?

    Homework Statement Deciede if the following are equivalence relations on Z. If so desribe the eqivalence classes i) a\equiv b if \left|a\right| = \left|b\right| ii) a\equiv b if b=a-2 Homework Equations The Attempt at a Solution i) \left|a\right| = \left|a\right| so its...
  37. F

    Sets and Algebraic Structures, help with equivalence relations

    Let Q be the group of rational numbers with respect to addition. We define a relation R on Q via aRb if and only if a − b is an even integer. Prove that this is an equivalence relation. I am very stumped with this and would welcome any help Thank you
  38. K

    Question about equivalence principle

    Let me restate my problem in a more clear way i think. Situation A: a accelerated rocket in flat spacetime. the observer in the rocket could think he is in a gravitation field equivalently.All experiments he do are like in a gravitation field downward. SituationB: a apple falls down under...
  39. K

    Can more than one photon participate in pair-production?

    Pair-production is the event when a particle and anti-particle is created from a single photon. We don't see 2 or more photons participating in a single pair-production event. Further, it seems in all the events of energy-mass conversion, photons act independently. Two or more photons can...
  40. D

    Tangent vectors as equivalence classes of curves

    defining a tangent vector v as the equivalence class of of curves: v = [\sigma] = \left. \frac{df(\sigma)}{dt} \right|_{t=0}, i want to show that this definition is independent of the member of the equivalence class that i choose. where \sigma represents a function from the reals to the...
  41. G

    PH at the equivalence point

    My book says that you cannot use the Henderson-Hasselbalch equation to find the pH at the equivalence point when titrating a weak acid with a strong base... I was wondering why not? it says that instead you must use the Kb of the conjugate base and that we find that from the Kw and the Ka...
  42. S

    Can Equivalence Principle Be Violated?

    Read about this experiment and the results obtained: http://www.physorg.com/news/2011-07-gyroscope-unexplained-due-inertia.html What's going on here? Why is the laser gyro accelerating? If this effect proves to be reproducible, would it not indicate the violability of the so-called...
  43. D

    Is there a connection between spin and KE/mass-energy equivalence?

    Bosoms (energy'ish) are 1 spin integers, Fermions (mass'ish) are 1/2 spin integers. KE=1/2MV^2 E=1MV^2 I've only been trying to wrap my puny mind around spin for longer than 10 years, these spins creates magnetic poles right? In all 3 dimensions?
  44. P

    Equivalence Classes in Physics: Tutorial Papers & Relationship to Units

    Are there any good, preferably tutorial, papers on equivalence classes with regards to theories of physics, and how they relate to units? Specifically, I'm looking for something that discusses that if you formulate the laws of physics in feet, then convert the units to inches, you haven't...
  45. L

    Pair Production and Mass Energy Equivalence

    Hello, In a previous discussion of Pair production I was shocked by what I heard and I have some questions from the general explanation of the subject. So you can make fermions out of bosons? You can make rest mass out of energy? Does this mean that not just relativistic mass, but...
  46. C

    Need to find the equivalence point volume from the first derivative graph?

    Homework Statement This was done in a lab, we titrated 0.2M NaOH with an unknown concentration of acetic acid. I've used excel to graph my first derivative of the data. Homework Equations (change in pH)/(Change in volume) The Attempt at a Solution My professor talked about drawing two trend...
  47. C

    What Determines the Number of Equivalence Classes in a Set?

    Homework Statement Lets say I have the word mississippi . Would I then say that I have 11 elements in my multiset . And would I say that I have 4 equivalence classes because I only have 4 different letters. If I had the set A={1,2,3,} Would I say this has 3 different...
  48. V

    Unraveling the Mystery of Mass-Energy Equivalence in Nuclear Reactions

    I was reading WikiPedia's entry on this, and there was one paragraph that surprised me: E = mc2 has sometimes been used as an explanation for the origin of energy in nuclear processes, but mass–energy equivalence does not explain the origin of such energies. Instead, this relationship merely...
  49. J

    Equivalence Principle precision

    I found 2 tables describing raising precision in experiments performed to investigate Equivalence Principle: http://en.wikipedia.org/wiki/Equivalence_principle#Tests_of_the_weak_equivalence_principle http://en.wikipedia.org/wiki/Hughes%E2%80%93Drever_experiment#Modern_experiments I can't...
  50. I

    Equivalence of 8 properties in Real Analysis

    Please help me prove that the following properties are equivalent Nested Interval Property Bolzano-Wierstrass theorem Monotonic sequence property LUB property Heine-Borel theorem archimedean property and cauchy sequence line connectedness...
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