User tacos_tacos_tacos - Mathematics Stack Exchange

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	724 reputation	bio	website		visits	member for	9 months
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4

16

votes

3

answers

361

views

How “abelian” can a non-abelian group be?

nov 13 at 16:24 Martino 254

3

11

votes

2

answers

241

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Algebraic interpretation of Lyapunov functions

abstract-algebra differential-equations

apr 1 at 20:05 Ilya 15.1k

1

8

votes

3

answers

207

views

What does an outer automorphism look like?

abstract-algebra group-theory intuition symmetric-groups group-actions

may 18 at 14:13 azimut 5,733

2

7

votes

5

answers

207

views

Simplest error detecting/correcting codes for math newbies

education coding-theory

feb 27 at 19:22 azimut 5,733

3

5

votes

1

answer

154

views

Showing that infinite product $\prod{(1+\frac{i}{k})}$ diverges

homework complex-analysis elementary-number-theory infinite-product

dec 5 at 5:52 WimC 9,228

5

votes

2

answers

217

views

What does a well ordering of $\mathbb{R}$ look like? [duplicate]

real-analysis order-theory axiom-of-choice

oct 8 at 8:10 Asaf Karagila 95.9k

4

votes

0

answers

28

views

Isomorphism between $E_8$ lattice and lattice defined by Extended Hamming Code

linear-algebra abstract-algebra combinatorics coding-theory

may 1 at 6:05 tacos_tacos_tacos 724

2

4

votes

3

answers

112

views

Special properties of $\mathbb{R}^3$

general-topology euclidean-geometry

jan 20 at 8:00 Community♦ 1

3

votes

1

answer

56

views

Using the 6 sets of sets of 5 disjoint 2-cycles and the 3 sets of 5 pairwise disjoint triangles to exhibit an outer automorphism of $S_6$.

abstract-algebra combinatorics group-theory finite-groups symmetric-groups

may 25 at 11:02 azimut 5,733

3

votes

1

answer

47

views

How many unique Hamming (7,4,3) Codes are there?

abstract-algebra combinatorics coding-theory

apr 27 at 10:29 Jyrki Lahtonen 31.9k

3

votes

1

answer

90

views

Classifying all ideals of a lattice $\mathbb{Z}[\sqrt{-d}]$

abstract-algebra ring-theory ideals factoring integer-lattices

dec 5 at 15:31 Thom Tyrrell 425

2

votes

1

answer

57

views

Linear stability analysis on a constrained three-dimensional system of ODE

differential-equations dynamical-systems nonlinear-optimization

apr 20 at 5:16 Glen O 3,302

1

2

votes

0

answers

209

views

What kinds of sets are reasonable to place on the continuum?

real-analysis soft-question mathematical-modeling economics

apr 15 at 8:15 tacos_tacos_tacos 724

2

votes

1

answer

72

views

Motivation for the term “transitive” group action

group-theory terminology group-actions

dec 11 at 7:35 Marc van Leeuwen 25.7k

2

votes

2

answers

75

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Why can we take integrals to find derivatives, and (kind of) vice-versa with complex functions?

complex-analysis integral

nov 2 at 5:20 Muphrid 3,934

1

2

votes

1

answer

172

views

How to calculate the residues of $\frac{\pi \cot(\pi z)}{1+z^2}$ at poles $i, -i, 0$

complex-analysis integral residue-calculus

nov 2 at 3:57 Michael Hardy 51.2k

2

votes

3

answers

194

views

Meaning of functions that vanish at a point

real-analysis functions convergence

oct 6 at 10:24 Norbert 21.2k

1

vote

2

answers

112

views

Classifying local behavior of fixed points using eigenvalues from linear stability analysis of 3D system

differential-equations dynamical-systems nonlinear-optimization

apr 23 at 20:34 nonlinearism 566

1

vote

1

answer

78

views

Why can't gradient systems have closed orbits?

differential-equations multivariable-calculus dynamical-systems

mar 28 at 2:28 Brian Rushton 3,208

1

vote

1

answer

45

views

Half-stable vs saddle node

differential-equations terminology dynamical-systems

mar 22 at 5:07 Amzoti 15.4k

1

vote

0

answers

37

views

Half-stable fixed point on a circle

differential-equations bifurcation

jan 29 at 5:04 tacos_tacos_tacos 724

1

vote

1

answer

197

views

Mean preserving spread vs higher variance

probability stochastic-processes economics

jan 27 at 2:35 joriki 93.6k

1

vote

1

answer

41

views

Using Smith Normal Form to prove that even for a singular square matrix with entries in field $F$, $\exists U$ nonsingular where $(UA)^2 = UA$

linear-algebra abstract-algebra field-theory

nov 20 at 13:38 Martin Argerami 17.8k

1

vote

0

answers

72

views

Finding a conformal map between an irregular region between two disks and an annulus

complex-analysis

nov 16 at 3:13 tacos_tacos_tacos 724

1

vote

1

answer

83

views

A proof that the hexagonal lattice describes the optimal sphere packing in two dimensions

abstract-algebra geometry packing-problem

nov 15 at 4:14 Gerry Myerson 87k

1

vote

1

answer

331

views

Obtaining a generator polynomial from a parity check matrix for a binary cyclic code

abstract-algebra generating-functions coding-theory parity

nov 12 at 12:33 Jyrki Lahtonen 31.9k

1

vote

2

answers

34

views

How can I demonstrate the image of a contour in $\mathbb{C}$?

complex-analysis

nov 9 at 11:30 Per Manne 4,449

1

vote

0

answers

72

views

Rank-nullity theorem and binary codes

linear-algebra abstract-algebra coding-theory

nov 6 at 1:15 tacos_tacos_tacos 724

0

votes

1

answer

37

views

Generating vectors of the face-centered cubic lattice

geometry number-theory quadratic-forms integer-lattices

apr 22 at 4:32 Will Jagy 22.4k

0

votes

3

answers

94

views

How to write “the parameter maximizing the maximum of the maximum value of two functions continuous in the domain of maximization”

algebra-precalculus multivariable-calculus optimization game-theory

apr 7 at 1:31 tacos_tacos_tacos 724

tacos_tacos_tacos

40 Questions