(cache) Mathematics Stack Exchange

0

votes

0

answers

4

views

predicate logic - function mapping outside of domain

predicate-logic

modified 1 min ago Thrasymaque 8

1

vote

0

answers

11

views

analysing a finite harmonic series sum

sequences-and-series

modified 2 mins ago scarface 706

0

votes

1

answer

10

views

Where to start on a basic derivation?

logic

answered 2 mins ago Bram28 17.1k

1

vote

0

answers

10

views

Distribute $a + b + c$ distinct balls into boxes $A, B, C$ such that $a$ balls, $b$ balls and $c$ balls go to boxes $A, B, C$

combinatorics discrete-mathematics combinations

asked 3 mins ago ape 6

0

votes

1

answer

12

views

How to find the limit function of a specific sequence of functions

real-analysis sequences-and-series

modified 5 mins ago DMcMor 2,009

0

votes

0

answers

2

views

Mal'tsev condition for a minority-term

universal-algebra

asked 5 mins ago Michael Hoefnagel 480

1

vote

0

answers

14

views

smooth $C^\infty$ anywhere but analytical $C^{\omega}$ nowhere function

calculus real-analysis

asked 5 mins ago 346699 509

1

vote

0

answers

11

views

Find the value of determinant

matrices determinant

asked 6 mins ago Dynamo 58

0

votes

1

answer

12

views

Finding out the inverse of elements

elementary-number-theory modular-arithmetic inverse

answered 7 mins ago Dragonite 462

1

vote

1

answer

10

views

Shuffled Convergent Sequence

analysis

modified 7 mins ago James Snell 17

1

vote

1

answer

25

views

Proof of identical eigenvectors

linear-algebra eigenvalues-eigenvectors

answered 7 mins ago user3658307 1,176

2

votes

1

answer

18

views

Function maps Cauchy sequences to Cauchy sequences: prove uniform continuity

real-analysis sequences-and-series continuity

modified 8 mins ago Robert Israel 257k

3

votes

1

answer

691

views

Variance stabilization for Poisson data

statistics random-variables transformation

modified 9 mins ago Community♦ 1

2

votes

0

answers

11

views

Can evolutionary biology processes be mathematically described?

stochastic-processes mathematical-modeling applications

asked 9 mins ago kryomaxim 2,181

0

votes

1

answer

9

views

Simple Probabilities

combinatorics

answered 9 mins ago Ross Millikan 224k

0

votes

0

answers

11

views

Finding a pole when the numerator is 0)

complex-analysis residue-calculus singularity

modified 10 mins ago SZN 1,597

2

votes

0

answers

7

views

Evaluate the following integral with variable upper limit

integration

modified 10 mins ago mathreadler 8,373

0

votes

0

answers

10

views

If $G$ is a finite cyclic group acting faithfully on $\mathbb{P}^1_\mathbb{C}$, must it have exactly two fixed points?

algebraic-geometry

modified 11 mins ago Amy 1,020

0

votes

0

answers

9

views

intersection of 3 planes

plane-geometry

modified 11 mins ago erfink 2,931

0

votes

0

answers

4

views

Use Cauchy's Integral Formula to express $f(0)$ as an integral on the circle $C(0, r)$

complex-analysis analysis cauchy-integral-formula

asked 12 mins ago user372834 61

2

votes

2

answers

25

views

Solve $x=e^{a/(b+x)}$ when $a,b,x>0$

calculus differential-equations exponential-function systems-of-equations

modified 12 mins ago Dmoreno 5,792

0

votes

0

answers

13

views

Proving Ramanujan's Nested Cube Formula

nested-radicals

asked 13 mins ago Crescendo 330

2

votes

1

answer

23

views

Average function of the first n-decimal digits.

real-analysis functional-analysis analysis probability-theory

answered 13 mins ago Ross Millikan 224k

0

votes

0

answers

21

views

To what extent should non-mathematicians learn proofs?

soft-question computer-science self-learning learning

modified 14 mins ago Tyler 130

0

votes

0

answers

15

views

show that the exterior derivative is still valid even when $\phi $ is not regular or a 1-1 function.

differential-geometry

modified 14 mins ago Trux 499

1

vote

1

answer

13

views

Find the minimal polynomial of -10-3i over the reals

abstract-algebra field-theory minimal-polynomials

answered 15 mins ago Arpan Sadhukhan 256

4

votes

2

answers

173

views

If $f(z)$ is entire, and $f(z)$ is real iff $z$ is real, prove $f'(z)$ is not equal to $0$ for all real $z$

complex-analysis

modified 18 mins ago rtybase 3,729

1

vote

0

answers

8

views

Difference in 1-1 vs many-1 Reducibility

computability

asked 18 mins ago gowrath 2,177

0

votes

0

answers

10

views

Proving Variance of Normal Distribution

probability normal-distribution

asked 18 mins ago Gentleman_Narwhal 47

0

votes

1

answer

19

views

How to calculate probability of one of two events?

statistics normal-distribution

modified 18 mins ago Roxy S 1

1

vote

1

answer

28

views

Prove that the critical value for the appearance of period 3-orbits in the tent map is $\frac{1+\sqrt5}{2}$

real-analysis dynamical-systems chaotic-systems

answered 19 mins ago Mark McClure 19.7k

0

votes

0

answers

3

views

How to use the Continuous Deep Q-Learning loss function

partial-derivative machine-learning neural-networks

asked 19 mins ago Bart 1

1

vote

2

answers

15

views

How to prove the divergence of a infinite product?

divergent-series infinite-product divergence

answered 20 mins ago Harald Hanche-Olsen 25.4k

-1

votes

0

answers

10

views

Matrices and Divisibility

matrices determinant

modified 26 mins ago Aman Sharma 334

5

votes

0

answers

27

views

Universal skew field of fractions

category-theory noncommutative-algebra universal-property

modified 29 mins ago Bib-lost 1,140

0

votes

0

answers

9

views

Bernoulli trials - Average?

combinatorics

asked 33 mins ago Mantas 43

0

votes

0

answers

11

views

Probability of the same letter answer being correct in a row on a test

probability

asked 34 mins ago Pro Q 113

0

votes

0

answers

6

views

Number of partitions into fixed number of parts?

combinatorics partitions

asked 34 mins ago Connor 632

0

votes

0

answers

5

views

If $f:\mathbb R^2\to \mathbb R$ is $\mathcal C^1$ how can we know that a stationary point is an extremum?

real-analysis

asked 34 mins ago user386627 446

1

vote

3

answers

12

views

Is $ G_{n,k} = \{ M \in M_{n\times n}(\mathbb{R}) ; \hspace{.1cm} \text{rank} (M) = k , M$ is symmetric and $ M ^2= M \}$ a manifold?

analysis manifolds smooth-manifolds

answered 35 mins ago Omnomnomnom 99.6k

4

votes

1

answer

99

views

The weak-star topology is Completely Hausdorff (in particular Hausdorff).

general-topology functional-analysis

answered 35 mins ago tomasz 20.3k

1

vote

1

answer

13

views

Please help me in this question.

permutations combinations

answered 37 mins ago Arpan Sadhukhan 211

3

votes

1

answer

42

views

Is i an integer? If so, i/1, which is i, is rational. 1 is an integer, at least.

philosophy

answered 38 mins ago Qiaochu Yuan 242k

0

votes

0

answers

10

views

System of three equation, find alpah for, one solution, no solution and infitne solution

matrices systems-of-equations

asked 38 mins ago Jason Taylor 1

0

votes

0

answers

8

views

Show that there are an equal amount of points on an infinite line and an infinite plane

real-analysis

modified 38 mins ago tilper 9,519

0

votes

0

answers

2

views

3 vectors function multipole expansion

calculus mathematical-physics spherical-harmonics coupling

asked 38 mins ago Toan Phuc 1

0

votes

0

answers

9

views

Finding Covariance using Variance

probability covariance variance

modified 38 mins ago nickgard 699

0

votes

0

answers

10

views

Problems with commuting matrices and determinant

matrices determinant

modified 39 mins ago M. Stefan 132

2

votes

0

answers

12

views

Intuition for Degree of a Map $S^n \rightarrow S^n$

algebraic-topology

asked 39 mins ago chilliBeanDream 140

0

votes

0

answers

5

views

Normal field continuous

differential-geometry

asked 42 mins ago Julio_fmat 33

1

vote

1

answer

11

views

Counterexample for approximating a Borel set with intervals and a distribution function

real-analysis measure-theory

answered 43 mins ago AreaMan 7,771

0

votes

0

answers

25

views

Can you prove the inequality?

inequality

modified 43 mins ago W.R.P.S 649

0

votes

0

answers

8

views

A detail in the proof that left invariant vector fields are smooth

lie-groups lie-algebras proof-explanation

asked 44 mins ago Soap 502

0

votes

1

answer

8

views

Question regarding validity of $\partial A = \partial(\mathbb{X} \verb!\!A) $ for a Hausdorff topology

general-topology numerical-methods

answered 46 mins ago tomasz 20.3k

1

vote

1

answer

25

views

If we have two invertible $2\times 2$matrices $A$ and $B$ with $BA=A^2B$, then how to show that one of the given conditions hold?

linear-algebra

answered 46 mins ago Starfall 11.3k

0

votes

0

answers

7

views

Being Close to a Unitary in a C$^{}$-algebra Implies Being Close to a Unitary in a Sub-C$^{}$-Algebra

functional-analysis operator-algebras spectral-theory c-star-algebras functional-calculus

asked 51 mins ago ervx 6,558

6

votes

2

answers

46

views

Find the solutions of equation $\{x\} + \{2x\} + \{3x\} + \{4x\}=3, x\in [0, 2017]$

elementary-number-theory

answered 55 mins ago Arpan Sadhukhan 246

2

votes

0

answers

15

views

What is $x$ satisfying the condition?

problem-solving transcendental-equations

asked 56 mins ago Lohith-kumar 124

1

vote

1

answer

17

views

Why is the stereographic projection a map from $S^2\to\mathbb{R}^2$?

differential-geometry manifolds riemannian-geometry stereographic-projections open-map

answered 1 hour ago Bernard 75.8k

0

votes

2

answers

20

views

Essential Singularity, proof without Casorati-Weierstrass Theorem

complex-analysis singularity

modified 1 hour ago Yiorgos S. Smyrlis 51.6k

4

votes

1

answer

65

views

Show that the series $\sum_{n=1}^\infty a_nb_n$ converges.

real-analysis convergence

answered 1 hour ago Siddhant 1,087

0

votes

0

answers

10

views

Convergence in $L^1([a,b])$ of $n \left(f\left(x+\frac{1}{n}\right) - f(x)\right)$ to the weak derivative of $f \in W^{1,1}(\mathbb{R})$

real-analysis functional-analysis

modified 1 hour ago Riku 61

0

votes

0

answers

9

views

Derivative of path along a function's root in terms of its Taylor expansion

calculus multivariable-calculus derivatives

asked 1 hour ago randomperson1 1

1

vote

1

answer

12

views

Cumulative Distribution Function of Z

probability probability-distributions random-variables

answered 1 hour ago Max 13.9k

0

votes

0

answers

11

views

Prove that if $f(x,y) \in W^{1,1}((0,1)\times (0,1))$ and $\partial_{x}f(x,y) = 0$ then $\exists$ $h(y) \in L^1(0,1)$ s.t. $f(x,y) = h(y)$

calculus real-analysis functional-analysis

modified 1 hour ago Riku 61

1

vote

1

answer

33

views

If two functions are equal, show that their derivatives satisfy this

derivatives vectors partial-derivative inner-product-space

answered 1 hour ago user3658307 1,176

3

votes

0

answers

12

views

Truncated taylor series inequality

calculus real-analysis asymptotics taylor-expansion

asked 1 hour ago J. Doe 16

0

votes

0

answers

16

views

How many elements of order 4 are there in Z/2 × Z/4 × Z/6

abstract-algebra

asked 1 hour ago Daniel McElroy 39

2

votes

1

answer

13

views

Probability based on dices

probability

answered 1 hour ago Bram28 17.1k

0

votes

0

answers

10

views

If the minimal polynomial of a matrix splits, then $A-\lambda I$ maps some vector outside an invariant subspace inside the space

linear-algebra matrices

asked 1 hour ago adrija 1,297

1

vote

0

answers

11

views

Existence of a probability measure

probability-theory measure-theory

asked 1 hour ago Tesla 853

3

votes

0

answers

22

views

Smallest subgroup of $S_4$ containing a set of permutations.

abstract-algebra group-theory symmetric-groups

modified 1 hour ago Justin 1,282

1

vote

0

answers

10

views

4th order tensors double dot product and inverse computation

linear-algebra abstract-algebra matrices tensor-products tensors

asked 1 hour ago Jeremy Diallo 6

95

votes

6

answers

21k

views

How to define a bijection between $(0,1)$ and $(0,1]$?

real-analysis functions elementary-set-theory

modified 1 hour ago leticia 1,361

1

vote

0

answers

12

views

spectral graph theory, is there any meaning for the magnitude of values in eigenvectors

eigenvalues-eigenvectors spectral-graph-theory

modified 1 hour ago Haohan Wang 151

0

votes

0

answers

11

views

modified gram schmidt equation proof

linear-algebra numerical-methods

asked 1 hour ago Thesinus 79

0

votes

0

answers

10

views

Help for derivation of least-squares FIR

integration

asked 1 hour ago a concerned citizen 157

4

votes

0

answers

49

views

Primes diving sum of binomial coefficients.

number-theory elementary-number-theory binomial-coefficients

modified 1 hour ago Toan Quang Pham 1,213

1

vote

2

answers

28

views

Verify if a span of vectors is $\mathbb{R}^2$

linear-algebra

modified 1 hour ago Thomas Andrews 112k

2

votes

1

answer

27

views

Number of observations needed to distinguish two known distributions with p-confidence

statistics probability-distributions

answered 1 hour ago Ladenkov Vladislav 11

1

vote

1

answer

9

views

Solve for $x=x_1 + x_2 $ $\tanh(x_1)+ \tanh(x_2)- \tanh(x_1) \tanh(x_2)A=B$

calculus

answered 1 hour ago Greg Martin 31.8k

1

vote

0

answers

21

views

Problem 4.139 from Volkoviskiy, Lunts, Aramanovich

complex-analysis residue-calculus

asked 1 hour ago AHN AHN 6

1

vote

2

answers

56

views

Find $\ \frac{\partial z}{\partial x}, \frac{\partial z}{\partial y}$ if $\ z=f(x,y)$

calculus differential-equations multivariable-calculus

modified 1 hour ago Mikko Pesonen 116

5

votes

0

answers

103

views

Lawvere's Sets For Mathematics Exercise 2.29c

elementary-set-theory category-theory topos-theory

modified 2 hours ago Geoffrey Sangston 36

2

votes

0

answers

26

views

How does Euclidean Domain imply Unique Factorization domain for Gaussian Integers?

abstract-algebra unique-factorization-dom gaussian-integers euclidean-domain

asked 2 hours ago Abdul Miah 68

0

votes

0

answers

5

views

The global dimension of a k algebra depends only on the simple modules

abstract-algebra projective-module global-dimension

asked 2 hours ago Werner Germán Busch 157

2

votes

0

answers

17

views

Twists and half-twists on ribbons in $\mathbb{R}^4$

general-topology algebraic-topology

modified 2 hours ago NoName 1,993

1

vote

1

answer

55

views

Counting Ballots?

combinatorics

modified 2 hours ago Community♦ 1

2

votes

0

answers

27

views

Maximum area of a pentagon

geometry

asked 2 hours ago luimichael 21

0

votes

2

answers

21

views

Proof by contradiction, Quantifiers

vector-spaces quantifiers

answered 2 hours ago Cerkal 36

0

votes

0

answers

7

views

conform mapping on a circular-arc bounded polygon

complex-analysis

modified 2 hours ago AHN AHN 6

1

vote

0

answers

10

views

Is it true that the function $\varphi (p)=\int { { |f| }^{ p } } d\mu $ is continuous?

functional-analysis measure-theory

asked 2 hours ago Paco Francisco 6

3

votes

0

answers

29

views

Geometric Interpretation of cochains and cocycles

algebraic-topology homology-cohomology

modified 2 hours ago Bang Pham Khoa 90

3

votes

0

answers

22

views

Problem with limit and increasing function

functional-analysis limits

asked 2 hours ago M. Stefan 132

2

votes

0

answers

9

views

Pearson Correlation Coefficient for samples $X,Y$ equals $1$ iff there is $a>0, b\in \mathbb{R}$ with $x_i = ay_i + b$ for every $i=1,\dots,n$.

statistics discrete-mathematics correlation descriptive-statistics

modified 2 hours ago Michael Hardy 171k

3

votes

0

answers

17

views

Seifert van Kampen proof for open coverings.

algebraic-topology

asked 2 hours ago Hanspeterwurst 45

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