Riemann Definition and 586 Threads

  1. icystrike

    Are the Cauchy-Riemann Equations Ever Satisfied for f(z) = |z|?

    Homework Statement What does it mean by this: The cauchy riemann equations are never satisfied when x and y are different from zero and when x=y=0 . Looking at the example of f(z)= l z l = \sqrt{x^{2}+y^{2}} Homework Equations The Attempt at a Solution
  2. Z

    An identity about Gamma and Riemann function

    we know that \Gamma (s)= \int_{0}^{\infty}dxe^{-x}x^{s-1} however every factor of the Riemann Zeta can be obtained also from a Mellin transform \int_{0}^{\infty}dxf(x)x^{s-1} =(1-p^{-s})^{-1} where f(x) is the distribution \sum_{n=0}^{\infty}x \delta (x-p^{-n}) is there any...
  3. S

    Basic Complex Analysis: Cauchy Riemann

    Homework Statement Let f be a holomorphic function in the unit disc D1 whose real part is constant. Prove that the imaginary part is also constant. Homework Equations Cauchy Riemann equations The Attempt at a Solution Hi guys, I'm working through the basics again. I think here we...
  4. S

    Compare Riemann Integration & Definite Integration Accuracy

    Can some please draw a comparison between Riemann Integration and normal definite integration in terms of accuracy.
  5. quasar987

    (anti)-symmetries of the Riemann curvature tensor

    The Riemannian curvature tensor has the following symmetries: (a) Rijkl=-Rjikl (b) Rijkl=-Rijlk (c) Rijkl=Rklij (d) Rijkl+Rjkil+Rkijl=0 This is surely trivial, but I do not see how to prove that Rijkl=-Rjilk. :( Thanks.
  6. F

    How would the world change if the Poincaré conjecture was proven?

    How would the world benefit from the Riemann hypothesis being solved? Mathematicians have been trying to solve this for over 100 years, but have been unable to due to it's mind-boggling complexity and difficulty. What would the world benefit if this theorem was to be solved?
  7. L

    Riemann hypothesis and number theory

    Would the field of the number theory collapse or flourish if the Riemann Hypothesis is proved as true?
  8. R

    Not riemann integrable => not lebesgue integrable ?

    "not riemann integrable" => "not lebesgue integrable"?? Hi, In general if a function is not Riemann integrable does this mean the function is also not Lebesgue integrable? Why or why not? I know that if the the function is Riemann integrable then its Lebesgue integrable, but I can't find...
  9. A

    Riemann vs. Lebesgue integral in QM

    When we talk about "Hilbert space" in (undergraduate) QM, we are typically talking about the space of square-integrable functions so that we can make sense out of \int_{-\infty}^{\infty} |\psi(\vec r,t)|^2 d^3x. But are we talking about Riemann-integrable functions or Lebesgue-integrable...
  10. M

    Riemann Integrability, Linear Transformations

    Homework Statement If f,g are Riemann integrable on [a,b], then for c,d real numbers, (let I denote the integral from a to b) I (cf + dg) = c I (f) + d I (g) Homework Equations The Attempt at a Solution I have the proofs for c I(f) = I (cf) and I (f+g) = I (f)...
  11. M

    Approximating integral using riemann sums

    Homework Statement f: [0,1] -> Reals, f(x) = 3-x2 P={0,1/2,1} Find lower and upper Riemann sums, and approximate the definate integral using them and find the corresponding approximation error. Homework Equations The Attempt at a Solution So I tried finding the upper Riemann...
  12. R

    The clue to the proof of Riemann hypothesis

    This could be the way to proof. remember, this is not a proof. today I found a clue to solution to Riemann hypothesis: Let it be Riemann zeta function :ζ(s) The proof that all the non trivial zeroes lie on the critical strip when s = 1/2 + it let us suppose there are other zeroes...
  13. H

    Unclear on Riemann Zeta Function

    After reading about the Riemann Zeta Function on Wolfram Alpha (http://mathworld.wolfram.com/RiemannZetaFunction.html), it's still unclear to me how the Euler product formula is essentially equal to the limit of a p-series. Someone please enlighten me
  14. C

    Show that the following function is Riemann integrable.

    Homework Statement Show that the function f: [0,1] -> R defined by: f(x) = 1, if x=1/k for some k f(x) = 0, else is Riemann integrable on [0,1] Homework Equations The Attempt at a Solution I attempted the problem using Cauchy's criterion but found that this function is...
  15. M

    Is f(x) = 1 if x is rational, 0 if x is irrational Riemann integrable on [0,1]?

    Homework Statement Let A={1/n, n =natural number} f: [0,1] -> Reals f(x) = {1, x in E, 0 otherwise Prove f is riemann integrable on [0,1] Homework Equations The Attempt at a Solution Not quite sure, but I think supf = 1 and inf f= 0 no matter what partition you take, then...
  16. A

    Left endpoint approximation & Riemann Sums (Sigma)

    1. The problem statement, all variables and givennown data 1)FInd the nth left endpoint approximation Ln for f(x) = 3x^2-2 on [0,2]. What is the limit as n approaches infinity Ln in this case? 2)Evaluate: \sum45i=5 (2i-5) Homework Equations Ln = \sumNj=1 f(cj)(xj-xj-1) The...
  17. R

    Cauchy riemann equations and constant functions

    Homework Statement Let f(z) be analytic on the set H. Let the modulus of f(z) be constant. Does f need be constant also? Explain. Homework Equations Cauchy riemann equations Hint: Prove If f and f* are both analytic on D, then f is constant. The Attempt at a Solution I think f need be...
  18. F

    Elliott-Halberstam conjecture and the Riemann Hypothesis

    I was wondering if one of the consequences of the Elliott-Halberstam conjecture would imply the Riemann Hypothesis (RH) or the Generalized Riemann Hypothesis (GRH)? Or at least if there is a connection between the Elliott-Halberstam conjecture and RH or GRH? I ask because the...
  19. O

    Calculate Riemann tensor according to veilbein

    Homework Statement How to use veilbein to calculate Riemann tensor, Ricci tensor and Ricci scalar? (please give me the details) de^a+\omega_{~b}^a\wedge e^b=0, R_{~b}^a=d\omega_{~b}^a+\omega_{~c}^a\wedge\omega_{~b}^c. The metric is...
  20. T

    Convergence of sum involving Mobius function (with Riemann Zeta)

    Hello everyone. I was hoping someone could clarify this "heuristic" argument I found online. First, what is the analytic function they speak of and is its derivative difficult to compute? Second, does this look like a legit argument? : If you take the derivative w.r.t s of both sides of sum...
  21. marcus

    Riemann Hypothesis and Quantum Mechanics

    Maybe someone will find something interesting in this paper. They have a reference to some 1995 work by Alain Connes. I didn't have time to look into this very much. Maybe it's amusing and maybe not: http://arxiv.org/pdf/1012.4665v1
  22. A

    Cauchy Riemann Equations (basic doubt)

    Lets say we have a function of a complex variable z , f(z). I read that for the function to be differentiable at a point z0 , the CR equations are a necessary condition but not a sufficient condition. Can someone give me an example where the CR equations hold but the function is not...
  23. C

    Fermi estimate of the week: Riemann hypothesis

    For those not familiar with the term Fermi estimate/problem/question see here: http://www.vendian.org/envelope/dir0/fermi_questions.html http://en.wikipedia.org/wiki/Fermi_problem My question: Between the time that Riemann posed his famous question (in 1859) and now, how many hours have...
  24. H

    Riemann Integrable <-> Continuous almost everywhere?

    Riemann Integrable <--> Continuous almost everywhere? I ran across a statement somewhere in the forums saying that a function is Riemann-integrable iff it is continuous almost everywhere, i.e. if its set of discontinuities has measure 0. Is that right? What about the case of a function...
  25. A

    What Definite Integral Does This Riemann Sum Represent?

    Homework Statement Rn=\sum(i*e^(-2i/n))/n^2, i=1 Identify this Riemann sum corresponding to a certain definite integral. Homework Equations The Attempt at a Solution I got till 1/n^2 [1/e^(2/n)+2/e^(4/n)+3/e^(6/n)...n/e^2] and that's it. To my understanding I should be...
  26. K

    Proof using Riemann Integral definition

    Homework Statement Suppose that f:[a, b] → ℝ is a function that is zero for all x ∈ [a, b] except for the values x_1,x_2,…,x_k. Find ∫[a b](f(x)dx) and prove your result. Homework Equations Definition of a Riemann integrable function...
  27. C

    A little renewed Disproof of Riemann hypothesis

    hmm...
  28. A

    General metric with zero riemann tensor

    A metric consistent with interval: \mathrm{d}s^2=-\mathrm{d}\tau^2+\frac{4\tau^2}{(1-\rho^2)^2}\left(\mathrm{d}\rho^2+\rho^2\mathrm{d}\theta^2+\rho^2\sin(\theta)^2\mathrm{d}\varphi^2\right) get zero for riemann's tensor, therefor must be isomorphic with minkowski tensor. But I don't find thus...
  29. T

    Math Real Analysis Problem, Riemann Sum Integral?

    Part 1. Homework Statement The problem literally states... " The Integral. limit of n-> infinity of n*[1/(n+1)^2 + 1/(n+2)^2 + 1/(n+3)^2 + 1/(2n)^2] = 1/2 " According to the teacher, the answer is 1/2. I don't know why or how to get there. Part 2. The attempt at a solution...
  30. M

    Suggestion for a good book on Riemann Surfaces - your personal experiences

    Hello everyone - I'm a third year student at Cambridge university, and I've recently started taking a course on Riemann surfaces along with a number of other pure courses this year. The problem is, the lecturer of the course is of a rather sub-par standard - whilst I don't doubt he's probably...
  31. B

    What is the different between Minkowski Space an Semi Riemann Space?

    Last summer I took Semi Riemann Geometry lesson. Almost all the definitions in Semi Riemann geometry are with the same Minkowski geometry. I don't understand what is the different between Minkowski Space an Semi Riemann Space.
  32. V

    Proof that f(x) = 1/sqrt(x) is Riemann Integrable

    Homework Statement The problem given is: Show that the function f(x) = 1/sqrt(x) is integrable on the compact interval [0,1]. Homework Equations We are only allowed to use theorems, definitions, and properties that have been covered in class or are in the book. The ones I...
  33. L

    What are the Functions of Riemann Invariants?

    Can someone tell me what a riemann invariant is in general terms please? i can't find it anywhere! thanks, lav
  34. D

    No. of field equations and components or Riemann tensor?

    no. of field equations and components or Riemann tensor?? Someone was trying to explain to me about curvature in space. From what I got from what they were saying doesn't make sense to me. I'm not sure I understand what the number of components, N, of R\alpha,\beta,\gamma,\delta when compared...
  35. arivero

    How Do the Riemann Zeta and Dirichlet Eta Functions Interact?

    Consider the separation of the Riemann Zeta function in two terms \begin{flalign*} \zeta(s) &= 1^{-s} + 2^{-s} + 3^{-s} + 4^{-s} + 5^{-s} + 6^{-s} + ... = & \\ &=(1^{-s} + 3^{-s} + 5^{-s} + 7^{-s} + 9^{-s}+ ... ) + ( 2^{-s} + 4^{-s} + 6^{-s} + 8^{-s} + ...)&=& \\ &= (1 - 2^{-s}) \zeta(s) +...
  36. D

    Riemann integrability of composite functions

    Hi, I'm stuck on this problem here about composite function, help is appreciated: Let g : [a,b] -> [c,d] be Riemann integrable on [c,d] and f : [c,d] -> R is Riemann integrable on [c,d]. Prove that f o g is Riemann integrable on [a,b] if either f or g is a step function I was able to solve...
  37. Rasalhague

    What Are Riemann Normal Coordinates in General Relativity?

    Sean Carroll: Lecture Notes on GR (2:20): Presumable to be a coordinate system it would have to exist at more than one point! Does he mean to define a Riemann normal coordinate system as a chart such that g_{\mu\nu} takes its canonical form and the first derivatives \partial_\sigma...
  38. P

    Analysis 2- Riemann integrable functions

    [b]1. If abs(f) is Riemann integrable on [a,b], then f is Riemann integrable on [a,b]. True or false (show work) [b]2. A function f is Riem Int iff f is bounded on [a,b], and for every epsilon>0 there is a partition P of [a,b] s.t. U(f,P)-L(f,P)<epsilon [b]3. I believe that this...
  39. C

    Disproved the Riemann Hypothesis?

    (Dis)proof of Riemann hypothesis,Goldbach,Polignac,Legendre conjecture I'm just an amateur and not goot at english ^^;
  40. W

    Does Time Variation Necessarily Imply Full Spacetime Metric?

    Background: Math: An affine parameter provides a metric along a geodesic but not a metric of the space, for example between geodesics. A connection provides an affine parameter, and a non-trivial connection gives rise to Riemann curvature. Given the existence of a connection with Riemann...
  41. M

    What is the Relationship Between Riemann Space and Relativity?

    Homework Statement Hello …….. I have a question about a statement mentioned in the book “Introduction to tensor calculus and continuum mechanics” . it is :- Where the space (Vn) is Riemann space . Is this statement really true ? Homework Equations The Attempt at a...
  42. G

    If supremum=infimum, is f Riemann integrable?

    This is my first time posting & I am not familiar with how to get all the correct math symbols or how to use Latex, so I did the best I could. Homework Statement Suppose f is bounded on [a,b] and there is a partition P* of [a,b] for which S(f,P*)=S(f,P*). Is f Riemann integrable on...
  43. Z

    A proposed Hamiltonian operator for Riemann Hypothesis

    HERE http://vixra.org/pdf/1007.0005v1.pdf is my proposed proof of an operator whose Eigenvalues would be the Imaginary part of the zeros for the Riemann Hypothesis the ideas are the following* for semiclassical WKB evaluation of energies the number of levels N(E) is related to the integral of...
  44. P

    I am taking issue with the Riemann Integral

    Basically from what I understand the integral of a function, say ∫x^2dx from say 0 to 1, can be represented as the supremum/infimum of the function values within each of a countably infinite number of vanishingly small intervals in the domain created by a countably infinite number of partition...
  45. J

    Riemann lebesgue lemma. wikipedia. 2010-06-26

    http://en.wikipedia.org/wiki/Riemann-Lebesgue_lemma Have I made a mistake when it looks to me that the Wikipedia proof on Riemann-Lebesgue lemma looks like nonsense? How are you supposed to use dominated convergence theorem there?
  46. A

    Why Use Supremum Instead of Maximum in Riemann Sums?

    Let f be a Riemann integrable function defined on an interval [a,b], and let P = \{a = x_0 < x_1 < \ldots < x_n = b\} be a partition of [a,b]. I don't understand why the definition of (say) the upper Riemann sum of f associated with P is always given as U(f,P) = \sum_{i=1}^n M_i (x_i -...
  47. A

    How can I convert the Riemann Sum into an Integral?

    If I have a function c(x,Δx) that gives the area between x and x + Δx of a function. The area under the function can be given by: Sum from j = 0 to n-1 of c(b/n j,c/b) As n tends to infinity and b is the upper limit of integration. How can I convert this from a sum into a integral? I'm not...
  48. A

    Riemann tensor: indipendent components

    Hi, thanks for the attention and excuse for my bad english. I'm studying general relativity and I have a doubt about the number of indipendent component of the riemann curvature tensor. We have two kind of riemann tensor: type (3,1) Rikml type (4,0) Rrkml There are also some symmetry...
  49. R

    Riemann integrable sequences of functions

    Let f_n : [0,1] → [0,1] be a sequence of Riemann integrable functions, and f : [0, 1] → [0, 1] be a function so that for each k there is N_k so that supremum_(1/k<x≤1) of |f_n(x) − f(x)| < 1/k , for n ≥ N_k . Prove that f is Riemann integrable and ∫ f(x) dx = lim_n→∞ ∫ f_n(x) dx I am really...
  50. K

    Integrability of f on (c,d) from (a,b): Proof

    Homework Statement If a<c<d<b and f is integrable on (a,b), show that f is integrable on (c,d) Homework Equations The Attempt at a Solution I know that f is integrable on (a,b) iff for all e>0 there exists step functions g and h such that g \leq f1(a,b) \leq h and I(g-h) <e (...
Back
Top