Mathematics Stack Exchange

0

votes

1

answer

18

views

Matrix with spectral radius 1 that converges

linear-algebra matrices convergence-divergence dynamical-systems spectral-radius

answered 2 mins ago user293794 2,445

0

votes

0

answers

2

views

Criterion for a contractive mapping to map its domain into itself

real-analysis calculus functional-analysis fixed-point-theorems contraction-operator

asked 2 mins ago user92360 885

3

votes

1

answer

288

views

Find a polynomial which has the full symmetric group $S_m$ as Galois group

abstract-algebra galois-theory

modified 2 mins ago mrtaurho 11.1k

0

votes

0

answers

11

views

Square-free factorization

abstract-algebra polynomials ring-theory

modified 3 mins ago Rachmaninov 21

1

vote

0

answers

6

views

Three Body Problem - how to find the Figure-eight solution?

numerical-methods numerical-calculus

asked 3 mins ago mathbbandstuff 457

2

votes

0

answers

23

views

Geometric Group Theory, Meier lemma 11.30 about a two-ended groups $G$

group-theory graph-theory geometric-group-theory cayley-graphs

modified 5 mins ago Asaf Karagila♦ 336k

3

votes

0

answers

30

views

Ampère's law with ellipse

physics elliptic-integrals

modified 7 mins ago relayman357 233

1

vote

0

answers

39

views

Generalization of Jensen's inequality

real-analysis probability probability-theory measure-theory jensen-inequality

modified 7 mins ago RobPratt 13.3k

2

votes

0

answers

16

views

Geodesics on cone with new metric and law.

ordinary-differential-equations geodesic

modified 8 mins ago Narasimham 27.4k

0

votes

0

answers

15

views

Is this proof valid about the monotonicity of this function?

functions derivatives monotone-functions

modified 8 mins ago melani 21

0

votes

0

answers

28

views

Eigen Vector Method Vs Correlation-Free Coordinates Transformation Method

eigenvalues-eigenvectors correlation

modified 12 mins ago GENIVI-LEARNER 258

0

votes

0

answers

13

views

How do I do the correct Laplace transform of this function

laplace-transform

asked 14 mins ago helloworld1235 163

1

vote

1

answer

18

views

Autonomous system corresponding to flow: $\Phi(t, x) = e^t(1 + x) − 1$

ordinary-differential-equations

modified 14 mins ago the_candyman 11.6k

0

votes

0

answers

11

views

Beta - Binomial conjugacy equivalent for 1 - B

probability statistical-inference binomial-distribution beta-function

modified 15 mins ago Erik Cristian Seulean 383

1

vote

1

answer

29

views

Inverse of a $\Bbb C\mapsto\Bbb C$ function

complex-analysis

modified 15 mins ago J.G. 76.1k

0

votes

0

answers

6

views

Long exact sequence of reduced homology groups

algebraic-topology homology-cohomology exact-sequence

asked 15 mins ago user745578 765

7

votes

1

answer

50

views

Prove Stirling's formula given that for $I_n = \int_0^{\pi/2} \sin^n\theta d\theta$ we have $I_{2n+1}/I_{2n} \rightarrow 1$

integration sequences-and-series approximation

answered 16 mins ago DodoDuQuercy 709

2

votes

1

answer

12

views

Computing singular points of curves, exercise 5.1 (Hartshorne)

algebraic-geometry commutative-algebra

modified 16 mins ago Siddhartha 493

0

votes

0

answers

7

views

How does a variance on the slope of one regression line make any sense?

regression variance slope

asked 17 mins ago KWilliamson 1

1

vote

1

answer

21

views

Is Schwarz's lemma about partial derivatives true almost everywhere for twice-differentiable function?

calculus differential-forms

answered 17 mins ago peek-a-boo 12.1k

0

votes

0

answers

6

views

Will a non quadratic Lyapunov function (Kullback–Leibler divergence) yield global stability?

control-theory optimal-control stability-in-odes stability-theory lyapunov-functions

modified 19 mins ago matrix777 11

0

votes

1

answer

15

views

Confidence interval for generalized variance (determinant of covariance matrix)

statistical-inference matrix-calculus estimation entropy

modified 20 mins ago cantorhead 739

0

votes

1

answer

8

views

How may I determine the x-difference between two circumference points on an edge-on circle?

trigonometry circles

answered 24 mins ago RocketScienceGuy 1

6

votes

1

answer

929

views

Is the minimal conjunctive normal form for positive formula unique? If so, how do you calculate it?

logic boolean-algebra conjunctive-normal-form

modified 25 mins ago Community♦ 1

2

votes

0

answers

16

views

A walk into the desert and back - have some hard-won answers but can't see the pattern

optimization

asked 27 mins ago Forero 21

0

votes

1

answer

36

views

$f$ is continuous $\iff\operatorname{Fr}(f^{-1}(B))\subseteq f^{-1}(\operatorname{Fr}(B))$

general-topology continuity

answered 27 mins ago Brian M. Scott 502k

2

votes

0

answers

28

views

My solution to this UW Madison qualifying exam problem

complex-analysis

modified 27 mins ago Simplyorange 499

0

votes

1

answer

27

views

Continuity of this Piecewise function $f:\mathbb{R}^2\to \mathbb{R}$

real-analysis limits multivariable-calculus continuity solution-verification

answered 27 mins ago user1337 7,356

0

votes

0

answers

6

views

Dimension of parameterized set of points $\{(x,y,z)\}$

algebraic-geometry polynomials parametric parametrization

asked 28 mins ago Indefinite 140

0

votes

0

answers

21

views

Solve this question,di/dt + 60i +300q=cos(20t)

ordinary-differential-equations first-order-logic differential

asked 31 mins ago seo times 11

0

votes

0

answers

18

views

Dwyer Morphisms stable under pushouts

category-theory

modified 32 mins ago Butterbrot 33

3

votes

0

answers

17

views

If $X$ and $Y$ are two ordered sets, how many orderings of $X \times Y$ exist that preserve the orderings of $X$ and $Y$?

combinatorics order-theory

asked 34 mins ago Dominic Shillingford 31

2

votes

1

answer

20

views

Compute $\pi_2(S^2 \vee S^2)$

general-topology algebraic-topology homotopy-theory cw-complexes

modified 36 mins ago Alekos Robotis 15.4k

1

vote

0

answers

10

views

Equivalent definitions of preserving limits - 2

category-theory limits-colimits functors

asked 37 mins ago user634426 1,917

0

votes

0

answers

16

views

On the Continuous Extension of Functions

general-topology functional-analysis

asked 39 mins ago user284331 47.6k

2

votes

0

answers

18

views

Maclaurin series as an orthonormal expansion of a Hilbert space

taylor-expansion hilbert-spaces inner-product-space

modified 41 mins ago Wilem2 236

0

votes

0

answers

12

views

Solution of a DE.

ordinary-differential-equations laplace-transform

asked 41 mins ago Antonio Hernandez 11

0

votes

0

answers

3

views

Solving 1D Poisson equation using finite element method and understanding the Galerkin orthogonality

analysis orthogonality finite-element-method poissons-equation galerkin-methods

asked 43 mins ago Jukka Aho 1

0

votes

0

answers

19

views

The consequences of Jacobi Triple Product Identity

sequences-and-series combinatorics theta-functions q-analogs q-series

modified 44 mins ago user1062 61

1

vote

0

answers

22

views

Normal series of finite nonsolvable group

abstract-algebra group-theory

modified 46 mins ago David Molano 2,596

2

votes

0

answers

19

views

What is the true status of the Lehmer totient problem?

number-theory elementary-number-theory reference-request totient-function open-problem

modified 49 mins ago JCAA 1,200

2

votes

1

answer

21

views

Show that if $A$ is a $m \times n$ matrix with $AA^T = 2J + 5I$ then $n \geq m$ ($J$ is matrix of ones)

linear-algebra

modified 51 mins ago Quang Hoang 14.8k

0

votes

0

answers

18

views

Need an Upper Bound for $L^2$-Norm of Integral of a Gauss Function in 2 Dimensions

real-analysis integration inequality norm lp-spaces

modified 53 mins ago David Hughes 478

1

vote

1

answer

18

views

Lagrange Multipliers to find the maximum and minimum values

optimization maxima-minima lagrange-multiplier

modified 58 mins ago Rodrigo de Azevedo 15.4k

0

votes

1

answer

20

views

Fourier transform of circulant or cyclic permutation matrix

linear-algebra matrices fourier-transform circulant-matrices permutation-matrices

modified 1 hour ago Rodrigo de Azevedo 15.4k

2

votes

0

answers

33

views

Number of different orders of $\{a_1,\cdots,a_7\}$ where $a_{k+1}-a_k\neq2$ for $a_k=1,2,\cdots7$ and $1\leq k\leq 6$

combinatorics elementary-number-theory

modified 1 hour ago Matteo 4,601

0

votes

0

answers

13

views

Three series theorem - convergence of $\sum X_n$ with $f_n(x) = \frac{1}{\pi} \frac{n}{1+(nx^2)}$

probability-theory

asked 1 hour ago Никита Васильев 1,629

1

vote

1

answer

14

views

Operator norm of an infinite diagonal matrix

matrices functional-analysis operator-theory infinite-matrices

modified 1 hour ago Rodrigo de Azevedo 15.4k

0

votes

3

answers

45

views

Convergence of series to analytic function

sequences-and-series complex-analysis

answered 1 hour ago Vercassivelaunos 31

2

votes

1

answer

24

views

Smith normal form and understand of the quotient

abstract-algebra group-theory exact-sequence integer-lattices smith-normal-form

modified 1 hour ago Rodrigo de Azevedo 15.4k

1

vote

0

answers

4

views

Show that the sesquilinear form is bounded

functional-analysis quadratic-forms sesquilinear-forms

asked 1 hour ago zbrads2 601

0

votes

0

answers

31

views

What does the norm of a multivector describes, geometrically?

geometry metric-spaces manifolds riemannian-geometry clifford-algebras

modified 1 hour ago Alexandre H. Tremblay 1,379

0

votes

1

answer

15

views

Prove that $f$ is $d-d_E$ continuous if and only if every $d_f$-open sets in ($X, d_f$) is $d$-open in ($X,d$)

metric-spaces

answered 1 hour ago Alp Uzman 2,679

0

votes

0

answers

23

views

Derive the recurrence relations

combinatorics recurrence-relations

asked 1 hour ago Leox 7,325

0

votes

0

answers

8

views

Find eigenvalues and eigenfunctions of a specific hilber-schmid integral operator.

functional-analysis hilbert-spaces

asked 1 hour ago 2132123 335

0

votes

0

answers

9

views

Confused about Burmann series coefficients to approximate $erf(x)$

integration sequences-and-series approximation error-function

asked 1 hour ago whn 153

0

votes

1

answer

13

views

Semi-analytic (analytic ?) form for circle integral

integration

modified 1 hour ago Jacky Chong 21.9k

1

vote

1

answer

22

views

Interpretation of the Brauer group via projective bundles

algebraic-geometry

answered 1 hour ago Sasha 7,828

2

votes

1

answer

25

views

Extensions of $\mathfrak{p}$-adic Valuation

algebraic-number-theory

modified 1 hour ago M. Wang 635

6

votes

0

answers

69

views

+50

Twisting prisms : Proving/Disproving my hypotheses

geometry 3d

modified 1 hour ago Pj30 617

3

votes

0

answers

22

views

How to solve this ODE system with an implied integration within it?

integration ordinary-differential-equations

modified 1 hour ago Aryadeva 23.6k

4

votes

2

answers

24

views

Probabilities in a Set of numbers

probability

answered 1 hour ago Especially Lime 28.2k

4

votes

1

answer

22

views

computing $\pi_1(\mathbb{R}P^2 \vee\mathbb{R}P^2)$ and $\pi_1(\mathbb{R}P^2 \times \mathbb{R}P^2)$

general-topology algebraic-topology homotopy-theory cw-complexes

answered 1 hour ago Maxime Ramzi 34k

0

votes

0

answers

12

views

$X=S^2/\sim$ where a point on the equator is identified with its antipodal point. Compute $\pi_1(X)$ and $H_\ast(X)$

general-topology algebraic-topology homology-cohomology homotopy-theory cw-complexes

asked 1 hour ago Zebramuscles1234 71

0

votes

0

answers

12

views

Determine $P(X + 2Y \leq 3)$ from $f_{X, Y}(x, y) = ke^{-\lambda x}$

probability probability-distributions

asked 1 hour ago Novice 129

2

votes

1

answer

27

views

Number of isoceles triangles formed by the vertices of a polygon that are not equilateral

combinatorics combinations triangles polygons

modified 1 hour ago Stranger Forever 631

2

votes

1

answer

10

views

Confluent Hypergeometric function

hypergeometric-function

answered 1 hour ago Robert Israel 379k

0

votes

0

answers

15

views

Does every compact $2$-manifold have a finite triangulation?

general-topology

modified 1 hour ago KReiser 27k

1

vote

1

answer

17

views

Littlewood's Second Principle : Simple function is continuous on restricted domain

real-analysis sequences-and-series measure-theory proof-explanation

modified 1 hour ago Martin Argerami 152k

1

vote

0

answers

6

views

How to find matrix representations for groups “moving along” integrals and differentials of functions?

calculus linear-algebra matrices soft-question

modified 1 hour ago verret 4,978

3

votes

0

answers

25

views

Formal grammar for a logic?

logic formal-languages formal-proofs

asked 1 hour ago Retracted 189

1

vote

2

answers

24

views

Integer solutions to $2^m - 3^n = p \cdot C$ where $m, n , p$ are positive integer variables and $C$ is a positive integer constant.

number-theory

answered 1 hour ago N. S. 119k

0

votes

0

answers

7

views

Wave maps, second energy inequality

differential-geometry riemannian-geometry tensors semi-riemannian-geometry tangent-spaces

asked 1 hour ago User1 1,143

0

votes

0

answers

15

views

Interesting question on - Graph Theory Narsingh Deo

graph-theory

asked 1 hour ago RichardCoouse 25

0

votes

0

answers

15

views

Problem on Locus involving ellipses

geometry coordinate-systems elliptic-curves elliptic-functions

modified 1 hour ago user238388 1

5

votes

0

answers

384

views

Prob. 12, Chap. 6, in Baby Rudin: Denseness of $\mathrm{C}[a,b]$ in $L^2[a,b]$

real-analysis integration analysis definite-integrals lp-spaces

modified 2 hours ago Saaqib Mahmood 19.8k

0

votes

0

answers

12

views

Stein factorization $X\to B'\to B$ and $k(B)$ is algebraically closed in $k(X)$

algebraic-geometry

asked 2 hours ago 6666 3,473

1

vote

0

answers

32

views

How to maximize functions with strange constraints?

optimization

modified 2 hours ago Rodrigo de Azevedo 15.4k

0

votes

3

answers

28

views

How to solve this system of equations with absolute values?

algebra-precalculus

modified 2 hours ago Aqua 70.9k

2

votes

0

answers

18

views

Are the two following automorphisms of a semisimple Lie algebra conjugated?

linear-algebra lie-algebras automorphism-group root-systems semisimple-lie-algebras

modified 2 hours ago James 450

0

votes

0

answers

8

views

Simple tilted perspective projection

geometry euclidean-geometry projective-geometry

modified 2 hours ago Sebastiano 1,558

0

votes

0

answers

4

views

unique solution of l1 minimizer is sparse

optimization norm sparsity

asked 2 hours ago mohammad 169

0

votes

0

answers

25

views

To evaluate $\sin(55°)$ with $10^{-4}$ error margin, how many terms are needed for the Taylor Series?

sequences-and-series analysis

modified 2 hours ago Colleg an Delta 43

0

votes

0

answers

12

views

Using MC to approximate an integral

monte-carlo simulation

asked 2 hours ago Wanderer 11

3

votes

0

answers

21

views

Norm on space of signed measures

functional-analysis measure-theory normed-spaces measurable-functions

modified 2 hours ago MathMath 361

14

votes

1

answer

150

views

Alternating Harmonic Series Spin-off

sequences-and-series

modified 2 hours ago Jaeseop Ahn 141

0

votes

0

answers

10

views

Solve matrix equation sum

matrices matrix-equations

asked 2 hours ago JDoe2 368

7

votes

2

answers

250

views

Prove that there exists a row or a column of the chessboard which contains at least √n distinct numbers.

combinatorics discrete-mathematics probabilistic-method

modified 2 hours ago Aqua 70.9k

0

votes

1

answer

26

views

Show that if $F,G, H$ are subspaces of $E$, then: $(F \cap G) + (F \cap H) \subseteq F + (G\cap H)$.

linear-algebra vector-spaces

modified 2 hours ago user1337 7,356

1

vote

0

answers

24

views

Every probability space can be embedded into a full probability space

probability-theory conditional-probability

modified 2 hours ago StubbornAtom 11.4k

1

vote

0

answers

18

views

+50

Which generalization of bipartite graphs is stronger?

bipartite-graphs hypergraphs

modified 2 hours ago Erel Segal-Halevi 8,763

6

votes

0

answers

72

views

How to understand the effect of adjoint functors?

category-theory limits-colimits adjoint-functors universal-property kan-extensions

modified 2 hours ago Bumblebee 13.2k

2

votes

0

answers

43

views

Lower bound on the roots of polynomial

combinatorics complex-analysis

modified 2 hours ago nukelawe 21

4

votes

1

answer

26

views

$\left(\sum_i a_i\right)^2\ge (n-1)\sum_i a_i^2 + b\implies 2a_i a_j \ge b/(n-1) \quad (\forall i\ne j)$

inequality summation cauchy-schwarz-inequality a.m.-g.m.-inequality

modified 4 hours ago Michael Rozenberg 156k

4

votes

1

answer

27

views

Is it possible to construct a Haar measure on a locally compact group assuming the existence of such a measure on compact groups?

functional-analysis measure-theory

answered 4 hours ago paul garrett 35.6k

5

votes

0

answers

37

views

Prove the following inequality $\sum_{k=0}^{n}(-1)^{k}f(a_{k})\geq f ( \sum _ { k = 0 } ^ { n } ( - 1 ) ^ { k } a _ { k } )$

calculus derivatives convex-analysis jensen-inequality

modified 4 hours ago Petter Green 53

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