Mathematics Stack Exchange

0

votes

1

answer

21

views

Find the area of an equilateral triangle

geometry euclidean-geometry triangles area

answered 1 min ago Katherine 2,263

0

votes

2

answers

14

views

Recurrence relation $a_{n+1} = 2 a_n -1$ with $a_0=3$. What is $a_n$ expressed as a function of $n$?

discrete-mathematics recurrence-relations recursion

answered 16 secs ago José Carlos Santos 313k

0

votes

0

answers

3

views

Show that for any x, x' E R^n of dimension n > 0, if for any y E R^n of dimension n > 0 one has x . y = x' . y, then x = x'.

multivariable-calculus

asked 2 mins ago Buzzy123 1

0

votes

1

answer

18

views

$\int_0^1 \frac{(1-x^2)xm^2}{m^2x^2+\lambda^2(1-x)} \, dx$?

calculus integration definite-integrals

answered 3 mins ago Raffaele 23.4k

18

votes

0

answers

161

views

Does there exist a real function with following properties?

real-analysis calculus

modified 5 mins ago N.Quy 1,030

0

votes

0

answers

2

views

How to measure the similarity between 2 circular sequences?

algorithms

asked 5 mins ago tctco 11

0

votes

1

answer

8

views

Translating a English Sentence to Predicate Logic

solution-verification predicate-logic logic-translation

answered 6 mins ago Ben Baker 119

10

votes

1

answer

310

views

+500

Meaning cone, ray, fan for polytopes

linear-algebra matrices polytopes convex-geometry convex-hulls

answered 6 mins ago LinAlg 16.4k

0

votes

0

answers

8

views

Convergence in the $A$-norm

linear-algebra normed-spaces numerical-linear-algebra positive-definite symmetric-matrices

asked 7 mins ago LisaB 13

0

votes

0

answers

7

views

Determine value of flow

ordinary-differential-equations

asked 8 mins ago kalashot 131

0

votes

0

answers

5

views

Using matrix algebra to solve a differential vector equation

multivariable-calculus physics tensors

asked 9 mins ago Gerald 67

0

votes

1

answer

26

views

Some algebraic manupilation of Fermat's last theorem

number-theory elementary-number-theory diophantine-equations

modified 9 mins ago player3236 12.5k

1

vote

1

answer

18

views

Let $R$ be an equivalence relation on $X$ and $S$ an equivalence relation on $X/R$…

elementary-set-theory equivalence-relations

answered 11 mins ago mathcounterexamples.net 51.2k

1

vote

1

answer

12

views

Show that if R is reflexive, then S is subset of R composition S

elementary-set-theory relations

modified 12 mins ago Asaf Karagila♦ 348k

0

votes

0

answers

3

views

Characterisation of complete riemannian manifolds using divergent curves

riemannian-geometry

asked 12 mins ago joseabp91 2,128

1

vote

1

answer

15

views

What's the difference between a “computational algorithm” and a “numerical algorithm”?

algorithms definition

answered 14 mins ago Patrick Stevens 32.4k

5

votes

1

answer

187

views

Bijection between multisets and directed animals?

combinatorics

modified 14 mins ago David Bevan 5,674

1

vote

0

answers

39

views

To which large cardinal property this inaccessible cardinal is equal?

set-theory large-cardinals

modified 16 mins ago Zuhair 2,451

0

votes

0

answers

7

views

For what values of $l$ and $j$ (simultaneously) is the following congruence solvable?($a \leq b$)

combinatorics number-theory elementary-number-theory modular-arithmetic solution-verification

asked 19 mins ago Confusion 307

0

votes

0

answers

8

views

Special case of graph-theory cycle

graph-theory

asked 20 mins ago Honza 317

0

votes

1

answer

17

views

conditional expectation of disjoint events

conditional-probability conditional-expectation conditional-convergence

modified 21 mins ago Surb 52.8k

1

vote

0

answers

18

views

What is $\text{inf} \{ \prod_{i=0}^{n}(x-i) ; n \in \mathbb{N_{0}} \}$ of relation $\sqsubseteq$?

real-analysis elementary-set-theory polynomials order-theory

modified 21 mins ago Hanul Jeon 23.7k

0

votes

0

answers

19

views

How do I know when I can do something to both sides in an inequality?

algebra-precalculus inequality

asked 22 mins ago Xetrez 139

0

votes

0

answers

5

views

$\mathcal A$ is a Banach algebra. Can there be two different $$ operators which both make $\mathcal A$ a $C^$-algebra?

operator-theory c-star-algebras banach-algebras

asked 23 mins ago Yuz 549

0

votes

1

answer

15

views

Trivial PDE problem with solving equation of the form u_x=x^n

partial-differential-equations

answered 24 mins ago Kosh 1,211

1

vote

0

answers

16

views

Solve Diophantine Equation

diophantine-equations

asked 25 mins ago newbie 63

0

votes

0

answers

33

views

Stars and bars problem

combinatorics discrete-mathematics

modified 28 mins ago user 16.8k

0

votes

0

answers

9

views

Determine the smallest 3D cuboid which entirely contains a domain-restricted parametric curve

calculus curves parametric

modified 28 mins ago Gary Allen 261

0

votes

0

answers

7

views

Chebyshev’s $\theta_1(x) = \sum_{n \leqslant x } (x-n) \Lambda_1 (n)$

number-theory prime-numbers analytic-number-theory chebyshev-function

asked 28 mins ago Walid Mohammed 67

0

votes

0

answers

25

views

Another form of the divergence theorem

calculus multivariable-calculus line-integrals divergence-theorem

modified 31 mins ago K.defaoite 4,900

0

votes

0

answers

10

views

Is the inequality $(n+1)!(2k)!(1+2k)!\geq (n+2k)!$ holds for all $n, k\in \mathbb{N}$

number-theory special-functions gamma-function beta-function

asked 34 mins ago user90533 550

0

votes

1

answer

23

views

A question related to cyclic extension and simple extension

abstract-algebra field-theory

answered 34 mins ago wangpengxin 33

0

votes

0

answers

18

views

How do I plot this graph?

graphing-functions machine-learning

modified 39 mins ago Artur D 1

5

votes

1

answer

33

views

Limitation of Henkin sematics in second order logic

compactness second-order-logic

modified 41 mins ago Peter Smith 46.5k

1

vote

0

answers

29

views

set function $G＝f-g$, then $f≦P$ and $g≦N$

real-analysis analysis

modified 41 mins ago bellow 1,575

6

votes

0

answers

100

views

The splitting field of polynomial over $Z/2Z$

abstract-algebra field-theory galois-theory finite-fields

modified 42 mins ago bellow 1,575

0

votes

0

answers

13

views

Gauss formula to calculate integral

integration divergence-theorem

asked 43 mins ago Trevor 343

2

votes

1

answer

40

views

Show that $ \operatorname{Hom}(K[s]/I, A)$ is isomorphic to $Z(I;A)$

abstract-algebra algebraic-geometry commutative-algebra

modified 43 mins ago user26857 42.7k

2

votes

0

answers

21

views

Raising a complex number to a large power

complex-analysis

asked 44 mins ago pkfly103 121

2

votes

1

answer

37

views

Calculating the improper integral $\int _{1}^{\infty}\frac{e^{\sin x}\cos x}{x}\,dx$

calculus integration improper-integrals

answered 30 secs ago Nandeesh Bhatrai 13

1

vote

1

answer

13

views

There is a plane given the equation. If a sphere is tangent to this plane, what is the equation for the sphere?(Sphere Center: ${M(4,-2.3)}$)

analytic-geometry plane-geometry spheres

modified 47 mins ago Gribouillis 9,493

3

votes

1

answer

31

views

How did they get an analytical solution to this second-order nonlinear PDE?

partial-differential-equations

answered 49 mins ago Bob Terrell 2,330

1

vote

1

answer

21

views

Show that $\lambda\in\sigma_p(T)$ iff $\overline\lambda\in\sigma_r(T')$

functional-analysis operator-theory hilbert-spaces banach-spaces spectral-theory

modified 55 mins ago 0xbadf00d 11.2k

0

votes

0

answers

14

views

Is the number pi algorithmically random in the Martin-Löf sense?

random pi

asked 57 mins ago M. Noll 9

-1

votes

0

answers

7

views

How to work with the Lag Operator in the denominator

time-series

asked 1 hour ago user824469 13

1

vote

0

answers

8

views

Joint Probability Boundaries

probability probability-theory probability-distributions

asked 1 hour ago walchi 11

1

vote

0

answers

7

views

Matrix approximation by eigenvalues approximation

matrices norm approximation svd

asked 1 hour ago sleeve chen 7,118

1

vote

0

answers

33

views

“solving iteratively”

sequences-and-series

modified 1 hour ago Lopey Tall 313

0

votes

0

answers

5

views

Gaussian function with dependent variables

probability-distributions normal-distribution gaussian

asked 1 hour ago Mune 9

9

votes

0

answers

83

views

+50

Size of a linear image of a cube in $\mathbb{Z}^d$

linear-algebra group-theory modules abelian-groups

modified 1 hour ago Michal Ferov 307

1

vote

0

answers

18

views

Vertex of degree $3$ in simple graph with at least 6 vertices, or its complement.

combinatorics graph-theory

modified 1 hour ago amWhy 200k

2

votes

0

answers

10

views

Finding a lower bound for a definite integral

calculus

asked 1 hour ago rwang 21

1

vote

1

answer

11

views

Vector field whose rotation is normal to a half ellipsoid

integration vector-analysis ellipsoids

answered 1 hour ago Sam Freedman 1,837

0

votes

1

answer

14

views

Mix of first price and second price auction problem.

solution-verification game-theory nash-equilibrium

answered 1 hour ago Nameless 3,540

1

vote

0

answers

6

views

Mathematical definition of G1 boundary conditions

analysis differential-geometry calculus-of-variations

asked 1 hour ago Mathsfreak 113

0

votes

0

answers

10

views

How to understand relaxation process? Is it connected with diffusion in mathematical?

probability partial-differential-equations physics

modified 1 hour ago Ailiy Evan 33

2

votes

0

answers

37

views

How to go from this summation to this approximation?

sequences-and-series summation summation-method

modified 1 hour ago kanalu_mk 21

0

votes

0

answers

20

views

Is it true that if $f$ is strictly convex and $d$ a metric, then $f\circ d$ is not a metric?

functional-analysis metric-spaces

modified 1 hour ago Davi Barreira 1,373

1

vote

2

answers

16

views

Evaluate/show the (elliptic) integral $\int_{0}^{\pi} \frac{ d \alpha}{\left[ 1 - k^2 \cos^2\left({\frac{\alpha}{2}}\right) \right]^{1/2}} = 2 K(k) $

integration definite-integrals elliptic-integrals

answered 1 hour ago mrtaurho 12.1k

0

votes

1

answer

8

views

Orthogonal group derived using tensor notation $f(v)=v_av_bm^{ab}$, instead of inner product notation $f(v)=v^Tv$?

matrices group-theory inner-products tensors orthogonal-matrices

answered 1 hour ago J.G. 97.1k

1

vote

1

answer

31

views

Show that $\int_0^\pi\frac{2\cos^2\left(\frac\alpha2\right)d\alpha}{\left[1-k^2 \cos^2\left(\frac\alpha2\right)\right]^{1/2}}=\frac4{k^2}[-E(k)+K(k)]$

integration definite-integrals elliptic-integrals

modified 1 hour ago mrtaurho 12.1k

1

vote

1

answer

39

views

Why $\boldsymbol{n} \approx \boldsymbol{n}^{+}$ contradicts the pigeon-hole theorem?

elementary-set-theory

modified 1 hour ago Ziqi Fan 892

0

votes

0

answers

22

views

Convergence of a sequence in a metric space

functional-analysis

modified 1 hour ago apa 133

0

votes

0

answers

8

views

Evaluating a finite series whose closed form found by a CAS involves $H_{-n}$ for positive-integer $n$

sequences-and-series harmonic-numbers computer-algebra-systems

asked 1 hour ago jwimberley 314

1

vote

0

answers

17

views

Result on a finite dimensional vector space and its subspace

linear-algebra vector-spaces linear-transformations

modified 1 hour ago Debprasad Kundu 111

0

votes

0

answers

9

views

Expected power of a determinant of a random matrix

random-matrices

modified 1 hour ago Machinato 1,976

1

vote

0

answers

12

views

Prove that $X$ and $Y$ have a finite expected value, where $X$ and $Y$ are independent and $X+Y$ has a finite first expected value.

random-variables expected-value independence

modified 1 hour ago math 2,135

12

votes

2

answers

228

views

Finding all natural $x$, $y$, $z$ satisfying $7^x+1=3^y+5^z$

number-theory elementary-number-theory exponential-diophantine-equations

modified 1 hour ago jlammy 6,404

2

votes

0

answers

18

views

Is it permitted to use $\tan 90^\circ$ to prove an equation/identity even if it is not defined? defined?

trigonometry

asked 1 hour ago Eyy boss 179

0

votes

0

answers

8

views

How to interpret the following random variable?

random-variables

asked 1 hour ago tappis 1

0

votes

0

answers

6

views

From site percolation to bond percolation

discrete-mathematics solution-verification percolation

asked 1 hour ago r00r 130

0

votes

0

answers

8

views

Existence of Cartan involution

reference-request lie-algebras semisimple-lie-algebras

asked 1 hour ago idok 1,554

2

votes

0

answers

36

views

Boundary of $M \times [0,1]$ where $M$ is a smooth manifold

differential-geometry manifolds smooth-manifolds manifolds-with-boundary

modified 1 hour ago IvanB 41

2

votes

0

answers

8

views

Operator on Sobolev Space w.r.t. Gaussian measure

functional-analysis operator-theory sobolev-spaces gaussian

asked 1 hour ago darkmatter 21

0

votes

1

answer

19

views

algebraic closure of residue field

algebraic-geometry commutative-algebra algebraic-number-theory

modified 1 hour ago Tsemo Aristide 79.8k

1

vote

0

answers

27

views

Topological entropy of the geodesic flow for manifold with non-negative constant sectional curvature and norms of Jacobi fields

differential-geometry riemannian-geometry dynamical-systems

modified 1 hour ago I don't know 3,428

0

votes

0

answers

11

views

Low bound for the probabilty that every node in a graph has at least one neighbor in a set of nodes from the graph

probability probability-theory conditional-probability probability-limit-theorems

modified 1 hour ago Idan Musayev 59

1

vote

0

answers

12

views

Book or a source to study time series analysis

time-series

asked 1 hour ago ARPIT GAUR 25

2

votes

0

answers

32

views

Spherical fusion categories: A certain functor

category-theory monoidal-categories natural-transformations topological-quantum-field-theory fusion-categories

modified 2 hours ago M.C. 1,093

1

vote

0

answers

11

views

To prove that it is possible to find a prime number q with a primitive root r such that ind(p) is a prime, for a particular prime p.

number-theory elementary-number-theory prime-numbers modular-arithmetic primitive-roots

asked 2 hours ago Pravimish 314

0

votes

0

answers

3

views

Convergence : $ ||u_n(.)||^2_v \rightarrow ||u(.)||^2_v$ in $L^1(]0,T[)$?

lp-spaces bochner-spaces

asked 2 hours ago user854662 59

2

votes

0

answers

19

views

Two questions about the initial value theorem for pdfs

probability laplace-transform initial-value-problems

modified 2 hours ago Boby 4,841

0

votes

0

answers

3

views

Characterising the affine image of a polar convex body

real-analysis geometry convex-analysis affine-geometry convex-geometry

modified 2 hours ago strawberry-sunshine 3,709

2

votes

2

answers

221

views

Ignoring units in unique factorization and divisibility theory

abstract-algebra number-theory

modified 2 hours ago Bill Dubuque 244k

0

votes

0

answers

13

views

Equivalent definitions of the krull dimension of a multi-graded k-algebra of finite type.

commutative-algebra graded-rings krull-dimension

modified 2 hours ago Eric Wofsey 259k

1

vote

2

answers

34

views

A non-abelian group of order $6$ is isomorphic to $\mathcal{S}_3$.

group-theory permutations finite-groups

modified 2 hours ago Shaun 27.4k

1

vote

0

answers

15

views

Unambiguous formal grammars for a specific class of languages

discrete-mathematics formal-languages automata context-free-grammar pushdown-automata

modified 2 hours ago Yanior Weg 13.4k

1

vote

1

answer

38

views

Basis of a linear transformation

linear-algebra matrices linear-transformations

modified 2 hours ago Stacker 906

1

vote

0

answers

14

views

Getting recurrence relations using generating functions

recurrence-relations generating-functions

modified 2 hours ago RobPratt 20.9k

0

votes

0

answers

34

views

Secret Santa Probability problem

probability derangements

modified 2 hours ago RobPratt 20.9k

1

vote

2

answers

21

views

Quadratic Equations Mathematical Method

quadratics

answered 2 hours ago Raffaele 23.4k

1

vote

0

answers

9

views

Computing Groebner Basis with given generators and relations of a module

commutative-algebra computer-algebra-systems groebner-basis macaulay2 singular-cas

asked 3 hours ago Mike V.D.C. 547

8

votes

0

answers

31

views

A problem on group rings from Isaacs Algebra, a Graduate Course

group-theory ring-theory group-rings

modified 3 hours ago Gary Jones 81

3

votes

0

answers

18

views

What is the distribution of quotients in Euclid's Algorithm

probability number-theory

modified 3 hours ago Colin McRae 51

4

votes

1

answer

22

views

Generalisation of an inequality to infinite dimensional normed linear spaces

functional-analysis inequality norm normed-spaces

modified 3 hours ago Salcio 511

4

votes

0

answers

31

views

What is the meaning of this Pigeon hole problem?

discrete-mathematics pigeonhole-principle

asked 3 hours ago ACA 41

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