Altruist - Badge - Mathematics Stack Exchange

Altruist

First bounty you manually award on another person's question.

Awarded 1348 times.

What makes the category of isocrystals over non-algebraically closed field non-semisimple?

Awarded Nov 27 at 11:34

François Gatine

3,0271 gold badge6 silver badges21 bronze badges

Can regularization (Abel/Borel) of a divergent derivative series tell us about $f'(x)$?

Awarded Nov 6 at 1:10

OscarTheGrumpyGrouch

1207 bronze badges

Prove that if $s_n\leqslant b$ for all but finitely many $n$, then $\lim s_n\leqslant b$.

Awarded Nov 3 at 8:42

iambadatnames

4910 bronze badges

Finding a upper bound on $||\nabla^2 f(x)||_{p,q}$ for p,q $\neq 2$ that is faster to calculate than eigenvalues or smaller.

Awarded Oct 22 at 13:17

Coo

238 bronze badges

Seeking a closed form for the sequence $a_n=\frac{a_{n-1}+a_{n-2}}{a_{n-1}-a_{n-2}}$, with $a_0=1$ and $a_1= 2$

Awarded Sep 12 at 14:20

Bryle Morga

17 bronze badges

Proof that matrix exponent elements belong to certain span

Awarded Sep 8 at 13:43

fredowick

356 bronze badges

Denominators of fractions are closed under gcd (vector gcds)

Awarded Sep 1 at 14:21

The Amplitwist

1,6304 gold badges17 silver badges30 bronze badges

If $G$ is a group of order $29 \cdot 30$, then $G$ has a normal Sylow-$29$ subgroup

Awarded Aug 24 at 17:00

algebra learner

59114 bronze badges

Is equality the same as identity?

Awarded Aug 8 at 2:37

Him

4553 silver badges19 bronze badges

Concrete Problems that can be solved by appealing to a Moduli Space

Awarded Aug 4 at 20:41

Vincent Tran

3491 silver badge11 bronze badges

Sum of two floors is equal

Awarded Jul 31 at 5:11

Richard Hall

1097 bronze badges

Proving (the lower bound that) $N$ exceeds product of primes under special congruence constraints

Awarded Jul 20 at 17:41

Ok-Virus2237

1071 silver badge11 bronze badges

Covariance of white noise smoothed by convolution with a squared exponential kernel

Awarded Jul 16 at 13:00

EHH

1,91312 silver badges22 bronze badges

Proof of Corollary to Theorem 1.25 in Shafarevich Basic Algebraic Geometry

Awarded Jul 6 at 7:27

zyy

1,2394 silver badges13 bronze badges

How to explicitly construct flat polynomial approximation to the exponential function?

Awarded Jul 2 at 15:05

Dang Dang

2882 gold badges5 silver badges25 bronze badges

Action of a group on a graph has a point moved freely

Awarded Jun 26 at 5:31

Edmaand Vlad Phiyik

1771 silver badge13 bronze badges

Infinite series of $1/9^{F_n}$ yields algebraic number?

Awarded Jun 21 at 11:26

Thinh Dinh

9,8906 gold badges22 silver badges59 bronze badges

How to show $\iint_R\frac{f(1,2)}{1+3u^2}\,dA=\iint_R\frac{f(2,1)}{1+3u^2}\,dA$?

Awarded Jun 18 at 16:08

epsilon

3,1551 gold badge5 silver badges42 bronze badges

How to connect polynomial multiplication to signal processing?

Awarded Jun 3 at 16:41

AL-zami

779 bronze badges

Prove the statement on $|x_n-x_m|<\frac{C}{|n-m|}$

Awarded May 29 at 19:17

uvw

1522 silver badges15 bronze badges

Minimum number of edges in a graph with $2n$ vertices such that each subgraph with $n$ vertices has at least $n$ edges?

Awarded May 26 at 4:06

Ross

1,3346 silver badges19 bronze badges

Is there a function $f$ such that the Cartesian graph $y=f(x)$ is the same curve as the polar graph $r=f(\theta)$?

Awarded May 19 at 2:36

Romogi

491 silver badge17 bronze badges

Are the sums $\sum_{n=1}^{\infty} \frac{1}{(n!)^k}$ transcendental?

Awarded May 12 at 16:33

Mason

4,6581 gold badge19 silver badges46 bronze badges

Points of a fiber product of schemes

Awarded May 9 at 9:21

Francis H.

9687 silver badges23 bronze badges

How to show that $f_a(x) = \frac{1}{2\pi} \frac{2^{a-1}}{\Gamma(a)} \bigl|\Gamma\bigl(\frac{a+i x}{2}\bigr)\bigr|^2 e^{x(\tau - \pi/2)}$ is stable?

Awarded May 7 at 3:27

K.defaoite

14.4k4 gold badges26 silver badges56 bronze badges

NFA of $k$ states recognizing all words of length $\le k$

Awarded May 5 at 21:02

MangoPizza

1,8568 silver badges27 bronze badges

Prove that a 'close' pair exists in a group of 100 people

Awarded May 4 at 13:02

Arthur_Kitsuragi

3151 silver badge14 bronze badges

Name of technique for solving a system of coupled ODEs using a complex combination?

Awarded May 4 at 12:52

Davide Masi

2,3131 gold badge6 silver badges29 bronze badges

How does one come up with this construction of approximating polynomials of $|x|$?

Awarded Apr 27 at 11:18

Юрій Ярош

2,0441 gold badge15 silver badges23 bronze badges

Solving for $f:\mathbb R_+\to\mathbb R_+$ with $f(xyf(x+y))=f(x)+f(y)$

Awarded Apr 21 at 23:53

Ѕᴀᴀᴅ

35.4k35 gold badges41 silver badges83 bronze badges

How to compute $\int_0^1\frac{\text{Li}_2(x^2)\arcsin^2(x)}{x}dx$ or $\sum_{n=1}^\infty\frac{4^nH_n}{n^4{2n\choose n}}$

Awarded Mar 31 at 5:11

Dennis

Quadratic optimization on a $d$-dimensional torus

Awarded Mar 14 at 18:31

Levent

5,30018 silver badges36 bronze badges

Adding Correction Factors on Integrals

Awarded Mar 14 at 4:25

Dylan Levine

2,1246 silver badges35 bronze badges

number of real solutions of $y^2+y=\sin(x)$ and $y+y^3=\cos^{-1}(\cos(x))$

Awarded Mar 8 at 6:30

Aadya Chaudhary

7992 silver badges18 bronze badges

Given a construction prove that the parallels that follow dont have a common perpendicular

Awarded Feb 28 at 12:52

Tutor4872

536 bronze badges

Existence of invariant subspaces (2)

Awarded Feb 18 at 6:57

San Ti

4131 silver badge11 bronze badges

Is the category $\mathbf{Rel}$ of relations balanced?

Awarded Feb 15 at 13:45

Jochen

13.2k1 gold badge26 silver badges45 bronze badges

Prove $\sum\limits_{\mathrm{cyc}} \sqrt{a+b} \ge \sum\limits_{\mathrm{cyc}} \sqrt{a + bc}$ for $ab + bc + ca + abc =4$

Awarded Feb 14 at 0:41

Tran Ngoc Khuong Trang

Integrals for $\pi-\frac{333}{106}$ and $\frac{355}{113}-\pi$

Awarded Feb 4 at 22:48

Alex

814 silver badges25 bronze badges

Find $n \equiv 0 \pmod{3}$ that form a sequence using integers from $1$ to $n$, with each term as the absolute difference of two previous terms.

Awarded Jan 28 at 18:58

babyaids

417 bronze badges

What is Moment Generating Function simply explained?

Awarded Jan 25 at 20:25

blue_egg

2,2932 gold badges11 silver badges41 bronze badges

Are there infinitely many primes $p$ such that $p\nmid 2^n+3^n+5^n$ for all natural $n$?

Awarded Jan 25 at 20:11

Carl Schildkraut

38.1k2 gold badges51 silver badges94 bronze badges

Height of all skyscraper

Awarded Jan 15 at 11:00

Nis Jørgensen

415 bronze badges

Necklace combinatorics problem

Awarded Jan 11 at 2:35

mathophile

4,7082 gold badges17 silver badges33 bronze badges

Probability a random integer has an $x$-bit prime factor (or two)

Awarded Jan 3 at 10:20

Simd

7792 silver badges20 bronze badges

Enumeration of Permutations of $0–9$ Satisfying Closure Under Doubling

Awarded Dec 8, 2024 at 6:21

permutation_matrix

1,0016 silver badges17 bronze badges

Does the sequence $\{\sin^n(n)\}$ converge?

Awarded Dec 6, 2024 at 16:04

Elvis

1,6771 silver badge19 bronze badges

Number made from the first digits of $2^n$

Awarded Dec 4, 2024 at 9:12

Math Admiral

1,7832 gold badges6 silver badges26 bronze badges

Proving that $\mu_x = \mu_{T(x)}$, where $\mu_x$ is the conditional measure associated to the $\sigma$-algebra of $T$-invariant sets

Awarded Dec 2, 2024 at 16:55

Hope

6312 bronze badges

Conjectured stronger form of the triangle inequality $a^{\frac{R\log 4}{R\log 4-r}}+b^{\frac{R\log 4}{R\log 4-r}}\ge c^{\frac{R\log 4}{R\log 4-r}}$

Awarded Nov 22, 2024 at 7:12

Ash_Blanc

1,2716 silver badges17 bronze badges

Solve the integral $\int_{0}^{\infty}\frac{\log(2-\cos(3x))}{1+x^2}dx$?

Awarded Nov 16, 2024 at 18:53

Amrut Ayan

9,3312 gold badges16 silver badges54 bronze badges

How did we discover the method of solving the linear 1st order ODE?

Awarded Nov 12, 2024 at 4:34

Integreek

9,0313 gold badges23 silver badges60 bronze badges

A series all of whose rearrangements are convergent, and yet not all rearrangements have the same sum?

Awarded Nov 9, 2024 at 11:03

Bruno B

8,3652 gold badges12 silver badges36 bronze badges

Confused by part of the proof of Stein's maximal principle

Awarded Nov 8, 2024 at 22:33

Lorago

12.7k2 gold badges13 silver badges37 bronze badges

(post deleted or otherwise unavailable)

Awarded Nov 4, 2024 at 9:05

Apoorva Shukla

3131 silver badge13 bronze badges

undecidable problems in Euclidean geometry

Awarded Oct 22, 2024 at 11:12

2080

2013 silver badges15 bronze badges

There exists a nonempty subsequence of $n$ integers within the range $[1, n]$, whose sum is equal to the sum of their indices.

Awarded Oct 22, 2024 at 1:15

abacaba

11.4k1 gold badge18 silver badges46 bronze badges

Simplifying expressions for reinvesting shares at fixed buy and dividend rates - manipulating floor functions

Awarded Sep 11, 2024 at 3:22

Srini

2,3651 gold badge15 silver badges25 bronze badges

Is the absolute value of a P.D.S. matrix P.D.S.

Awarded Sep 9, 2024 at 23:38

Ben Bolker

2862 silver badges15 bronze badges

Polynomial $f(x)$ has positive coefficients and all roots as real. How many polynomials formed from terms of $f(x)$ also have only real roots?

Awarded Aug 27, 2024 at 8:22

Fetray

941 silver badge19 bronze badges

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