Revival - Badge - Mathematics Stack Exchange

Revival

Answer more than 30 days after a question was asked as first answer scoring 2 or more. This badge can be awarded multiple times.

Awarded 23076 times.

Is there a combinatorial proof that the Catalan number $C_n$ satisfies $(n+1)C_n={2n \choose n}$?

Awarded 7 hours ago

Dean Rubine

5644 silver badges12 bronze badges

How could Feynman have modeled this computer routing problem with partial difference equations?

Awarded 9 hours ago

Theo H

2872 silver badges11 bronze badges

How to solve the Sylvester matrix equation $AX+XB=C$ for $X$?

Awarded 15 hours ago

draks ...

18.8k8 gold badges68 silver badges210 bronze badges

Dual Jacobi identity for Lie bialgebra

Awarded 19 hours ago

Marco Farinati

5063 silver badges9 bronze badges

Multiplication of surreal ordinals

Awarded yesterday

ViHdzP

4,9522 gold badges21 silver badges53 bronze badges

How do we know that is not possible to invert $x=t+\cos t$ analytically?

Awarded yesterday

pregunton

6,4002 gold badges32 silver badges54 bronze badges

Convergence of a Zeta-Zeta function

Awarded 2 days ago

Conrad

33.2k3 gold badges23 silver badges45 bronze badges

Compute the Scheme-Theoretic Fibers

Awarded 2 days ago

Viktor Vaughn

21.1k2 gold badges45 silver badges75 bronze badges

Expectation of the number of cards drawn without replacement until get all four aces (using conditioning)

Awarded 2 days ago

true blue anil

49.7k4 gold badges32 silver badges67 bronze badges

How many groups of order $2^2\cdot 3^2\cdot 5^2\cdot 7^2\cdot 11^2\cdot 13^2$ exist?

Awarded 2 days ago

Max Horn

2,67621 silver badges36 bronze badges

(2,3,7) tiling of Hurwitz surface

Awarded 2 days ago

Viktor Vaughn

21.1k2 gold badges45 silver badges75 bronze badges

Analytical solution for a linear matrix equation

Awarded 2 days ago

Zamu

3772 gold badges5 silver badges10 bronze badges

Preferential sampling and balls form the urn

Awarded 2 days ago

feecle6418

363 bronze badges

Markov Chain Question using probability generating function

Awarded 2 days ago

Tan Yong Boon

4613 silver badges11 bronze badges

Modelling a Water Rocket. Requires Some Validation and Help. ( WARNING : Extremely Long but Interesting Post )

Awarded Nov 28 at 2:24

138 Aspen

1,3575 silver badges31 bronze badges

Tangent line of a lemniscate at (0,0)

Awarded Nov 27 at 7:25

Kamil Jarosz

5,1023 gold badges20 silver badges36 bronze badges

Proving the Zig-Zag Lemma

Awarded Nov 26 at 17:53

Samuel Johnston

8245 silver badges11 bronze badges

How can we calculate the sum of sines or cosines where the angles are in geometric progression?

Awarded Nov 26 at 17:53

Dhairya Kumar

19017 bronze badges

$V'\otimes_K W \cong \operatorname{Lin}_K(V,W)$ via the Universal Property

Awarded Nov 26 at 17:02

Vladimir Lysikov

5,4502 gold badges21 silver badges35 bronze badges

Linear Algebraic Group whose elements have finite order is finite

Awarded Nov 26 at 12:34

D_S

36.3k7 gold badges60 silver badges177 bronze badges

Is there a set-based semantics for the untyped lambda calculus?

Awarded Nov 26 at 4:27

Lê Thành Dũng 'Tito' Nguyễn

4623 silver badges11 bronze badges

Is there any known application for normal numbers?

Awarded Nov 26 at 4:01

Qiaochu Yuan

477k55 gold badges1.1k silver badges1.5k bronze badges

extension of valuation rings

Awarded Nov 26 at 4:01

Uri Brezner

6156 silver badges9 bronze badges

product of equidimensional varieties is equidimensional?

Awarded Nov 25 at 20:35

e_s_

1,7819 silver badges22 bronze badges

Solve the equation in the following question

Awarded Nov 25 at 14:10

Dhairya Kumar

19017 bronze badges

Partial sum of squared binomial coefficients

Awarded Nov 25 at 14:10

Claude Leibovici

298k55 gold badges131 silver badges326 bronze badges

Elliptic Constructibility of the Heptagon

Awarded Nov 25 at 13:21

Oscar Lanzi

51.2k2 gold badges56 silver badges137 bronze badges

Intuitive understanding of Bezout's Identity?

Awarded Nov 24 at 17:49

Juan Martinez

314 bronze badges

Surface area of sphere using Dirac delta

Awarded Nov 24 at 17:24

lightxbulb

2,4381 gold badge15 silver badges27 bronze badges

Loop group and affine grassmannian

Awarded Nov 23 at 20:21

jackson

1,0475 silver badges20 bronze badges

Show that $\mathfrak{Re}(\textrm{Li}_2(e^{ix}))=\frac{x^2}{4}-\frac{\pi x}{2}+\frac{\pi^2}{6}$ (polylogarithm)

Awarded Nov 23 at 17:47

Claude Leibovici

298k55 gold badges131 silver badges326 bronze badges

Fourier transform from the fourier series

Awarded Nov 23 at 17:30

Steven Clark

9,3462 gold badges16 silver badges31 bronze badges

$G/H$ contains element of order $n$ but $G$ does not

Awarded Nov 23 at 10:50

Michael Albanese

105k22 gold badges227 silver badges494 bronze badges

Algebraic Hartog's lemma reduce to the affine case

Awarded Nov 23 at 6:49

Z Wu

2,57912 silver badges20 bronze badges

Show that $x(\pi - x)= \frac{\pi^2}{6}-\sum_{k=1}^{\infty} \frac{\cos(2kx)}{k^2}$

Awarded Nov 23 at 6:11

dantopa

10.9k10 gold badges46 silver badges86 bronze badges

Find Greens function associated with quadratic form

Awarded Nov 23 at 4:38

Daniele Tampieri

11k16 gold badges26 silver badges58 bronze badges

How many natural numbers are needed to generate 14 distinct subsets under complement and multiplicative closure?

Awarded Nov 22 at 22:52

mathematrucker

1,66112 silver badges24 bronze badges

Cubic non-residue calculation

Awarded Nov 22 at 19:57

Jeff Margrave

535 bronze badges

Necessary and sufficient conditions for the convergence of a series of complex terms

Awarded Nov 22 at 10:13

Daniele Tampieri

11k16 gold badges26 silver badges58 bronze badges

Convex Optimization of 3 Terms with 2 Non Smooth

Awarded Nov 22 at 1:40

Royi

10.6k8 gold badges56 silver badges118 bronze badges

No eigenvalue of a graph is larger than the maximum degree

Awarded Nov 21 at 20:48

minh quý lê

3051 silver badge13 bronze badges

Generalization of Weyl asymptotic law

Awarded Nov 21 at 18:20

LL 3.14

14.4k2 gold badges17 silver badges55 bronze badges

In which sense are the Cauchy-Riemann equations elliptic

Awarded Nov 21 at 10:00

subrosar

5,3101 gold badge13 silver badges34 bronze badges

Definition of bubbles and Removal of singularities

Awarded Nov 20 at 21:42

Emilia

3,1162 gold badges5 silver badges24 bronze badges

$D(F\circ u)=(F'\circ u)Du$ (chain rule) in Sobolev spaces - still hold when $F'$ discontinuous or when $F$ only weakly diff'ble?

Awarded Nov 20 at 19:23

Kadmos

3,8012 gold badges9 silver badges35 bronze badges

Advantages and disadvantages of EKF versus UKF

Awarded Nov 20 at 12:48

user515430

463 bronze badges

Formula for $\sin(\pi/n)$ with $n$ a positive integer

Awarded Nov 19 at 15:34

Bruno Andrades

5,4521 gold badge17 silver badges35 bronze badges

About the proof that Lebesgue measure is a premeasure.

Awarded Nov 19 at 14:42

Markus Scheuer

113k7 gold badges107 silver badges253 bronze badges

Image of a sphere contains the boundary of the image of a ball

Awarded Nov 19 at 1:51

Moishe Kohan

113k8 gold badges157 silver badges269 bronze badges

Prove that a monotone and surjective function is continuous

Awarded Nov 18 at 17:37

Daniel Smania

8,9771 gold badge10 silver badges33 bronze badges

Does $\sum_{n=1}^{\infty}\frac{1}{n^{f(n)}\left(\sin n\right)}$ converge? ( When $n$ approaches infinity, $f (n)$ also tends towards infinity)

Awarded Nov 18 at 17:10

Bruno Andrades

5,4521 gold badge17 silver badges35 bronze badges

Finding a minimal set of equations that determine a variable.

Awarded Nov 17 at 16:56

Max

14.8k25 silver badges43 bronze badges

Estimating the root of the equation $𝑎^𝑥+𝑏^𝑥=𝑐^x$ for triangle with sides $𝑎,𝑏,𝑐$

Awarded Nov 17 at 16:56

Claude Leibovici

298k55 gold badges131 silver badges326 bronze badges

Integrals that have yet to be solved - are there any?

Awarded Nov 17 at 13:41

Antonio

1261 silver badge5 bronze badges

Understanding the persistent homology groups

Awarded Nov 17 at 8:53

compact

585 bronze badges

Combinatorics - distribution of objects into boxes

Awarded Nov 16 at 11:04

true blue anil

49.7k4 gold badges32 silver badges67 bronze badges

$(k,l)$ shuffle and wedge product

Awarded Nov 15 at 23:05

krm2233

8,1393 silver badges25 bronze badges

Riemann $\zeta$-function and a series involving Stirling numbers of first kind.

Awarded Nov 15 at 14:49

DroneBetter

6744 silver badges18 bronze badges

Is there a way to calculate $ \sum_\limits{k=0}^{n}\sin({2^{k}x})$?

Awarded Nov 15 at 11:38

Dhairya Kumar

19017 bronze badges

Pointfree topology via Convergence

Awarded Nov 15 at 10:00

JH vd Walt

1715 bronze badges

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