Mathematics Stack Exchange

1

vote

1

answer

16

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How to estimate time to reach X with an exponentially increasing growth rate

calculus

answered 3 mins ago Ross Millikan 341k

0

votes

5

answers

14

views

$\forall n\in\mathbb{N}$, $a_n\not=0$, $\lim_{n\to\infty} a_n=0$. Find $\lim_{n\to\infty} \frac{\sqrt{3+a_n}-\sqrt{3}}{a_n}$

real-analysis calculus

answered 4 mins ago Michael Rozenberg 161k

0

votes

0

answers

5

views

$w(x,y)=f(x, y, g(x, y))$ where $f$ and $g$ are both differentiable. Write $\partial w / \partial x$ in terms of partial derivatives for $f$ and $g$.

calculus

asked 6 mins ago Mike 1

0

votes

0

answers

46

views

Prove that $11,111,111…$ is not a perfect square

elementary-number-theory contest-math solution-verification repunit-numbers

modified 6 mins ago sai-kartik 1,722

0

votes

2

answers

19

views

On probability and density functions

probability probability-distributions random-variables

answered 40 secs ago Graham Kemp 103k

-1

votes

0

answers

4

views

Probability of difference of 3 events

probability

modified 1 min ago Aryadeva 24.6k

0

votes

0

answers

5

views

Fiber product of the pullback along a covering space and the induced covering space from the preimage of the fundamental group

covering-spaces fundamental-groups fiber-bundles

asked 7 mins ago Katherine 229

0

votes

0

answers

5

views

Examples for understanding the maximum modulus theorem

complex-analysis

asked 8 mins ago zik2019 317

1

vote

1

answer

27

views

D'Alembert's formula with initial conditions hidden

partial-differential-equations wave-equation initial-value-problems

answered 8 mins ago runway44 5,498

1

vote

0

answers

7

views

A sequence with Supremeum at least 1

real-analysis sequences-and-series inequality supremum-and-infimum upper-lower-bounds

modified 9 mins ago gt6989b 46.5k

0

votes

1

answer

15

views

Defining a quotient field of a field using multiplicative subgroup possibly?

abstract-algebra group-theory field-theory definition quotient-group

modified 10 mins ago AbstractAlgebraLearner 16.9k

0

votes

0

answers

8

views

A matrix and linearly independent vectors

matrices vectors

modified 10 mins ago emeraldthread 1

1

vote

0

answers

5

views

Generalized Likelihood Ratio Test for $X_1\sim \text{Bin} (n_1,p_1)$ and $X_2\sim\text{Bin}(n_2,p_2)$

statistics hypothesis-testing

modified 18 mins ago Noe Vidales 725

4

votes

2

answers

91

views

if $a^5+b^5<1$ and $c^5+d^5<1$ then prove that ${a^2}{c^3}+{b^2}{d^3}<1$

multivariable-calculus inequality proof-writing holder-inequality

answered 19 mins ago nguyenhuyen_ag 1,218

2

votes

0

answers

23

views

Inverse image of compact is compact

general-topology

modified 24 mins ago A learner 1,390

2

votes

1

answer

60

views

What do “soundness” and “completeness” mean?

logic terminology computer-science rewriting-systems

answered 24 mins ago Graham Kemp 103k

0

votes

1

answer

14

views

Understanding upper set preorders

order-theory

answered 26 mins ago William Elliot 15k

4

votes

0

answers

81

views

After $2013$ such transformations, how many number $2013$ are there on the line if the given numbers are $1$ and $1000$?

combinatorics number-theory elementary-number-theory contest-math

modified 29 mins ago Shubhangi 1,525

-1

votes

0

answers

23

views

Prove that $\ell^\infty$ is a metric space

functional-analysis metric-spaces

modified 29 mins ago Alonso Delfín 5,343

0

votes

0

answers

10

views

$f(x, y(x))=0$ Show that $y'=-\frac{\partial f / \partial x}{\partial f/ \partial y}.$

calculus analysis

modified 31 mins ago Mike 1

1

vote

0

answers

10

views

What would be the most economical speed to operate the truck for a given distance?

calculus maxima-minima

modified 31 mins ago Lucifer Chase 11

1

vote

1

answer

25

views

The correct way to handle quaternions and rotations?

rotations quaternions

answered 32 mins ago runway44 5,498

0

votes

1

answer

13

views

Apostol problem : find $T(e_2-e_1)$ and determine the nullity and rank of $T$.

linear-algebra

modified 35 mins ago A learner 1,390

-2

votes

1

answer

71

views

Is $\operatorname{Proj}\longrightarrow\operatorname{Spec}$ a closed immersion?

algebraic-geometry schemes affine-schemes projective-schemes

modified 41 mins ago Stahl 19.3k

1

vote

1

answer

18

views

Asymptotic Estimate of Vector Function

multivariable-calculus asymptotics estimation parameter-estimation

answered 43 mins ago Claude Leibovici 163k

1

vote

1

answer

12

views

Linearize product of Two Special Ordered Sets and minimize number of variables

optimization nonlinear-optimization linearization

answered 47 mins ago LinAlg 13.4k

0

votes

1

answer

7

views

How can the topological characteristics of ergodic Markov chains be used to implement an algorithm to generate such Markov chains?

graph-theory algorithms markov-chains ergodic-theory

answered 48 mins ago Misha Lavrov 69.3k

1

vote

0

answers

47

views

Drunk man at the cliff problem: expected reward while staying alive?

probability probability-distributions markov-chains markov-process random-walk

modified 51 mins ago Andeanlll 313

1

vote

0

answers

13

views

Negative Volume

geometry multivariable-calculus

asked 57 mins ago soobster 948

-1

votes

0

answers

10

views

Let Ube a bounded , open subset of R^n, and suppose ∂Uis C^1. Assume n<p≤∞,and u∈W^(1,p) (U). Prove u has a version u^*∈C^(0,γ) (U┴-) , for γ=1-n/p,

functional-analysis partial-differential-equations banach-spaces lp-spaces sobolev-spaces

asked 57 mins ago A Rahman 1

-1

votes

0

answers

30

views

Sorting a set in least number of steps

combinatorics graph-theory algorithms order-theory directed-graphs

modified 57 mins ago Subham Jaiswal 2,528

1

vote

0

answers

43

views

+50

How can I prove the dimension axiom here?

algebraic-topology homology-cohomology

modified 58 mins ago Eric Wofsey 244k

0

votes

0

answers

4

views

Show that a Wiener Process $X(t)$ is a normal process?

stochastic-processes

modified 59 mins ago Kenta S 4,066

0

votes

1

answer

12

views

Prove that surjective endomorphisms of modules over a commutative Artinian ring with unity are isomorphisms

ring-theory modules

answered 1 hour ago rschwieb 125k

5

votes

2

answers

302

views

functions satisfying $f(x - y) = f(x) f(y) - f(a - x) f(a + y)$ and $f(0)=1$

functional-equations

modified 1 hour ago Mohsen Shahriari 3,753

0

votes

0

answers

33

views

Transporting Tangent Vectors when Taking Lie Derivatives

derivatives differential-geometry manifolds vector-fields lie-derivative

modified 1 hour ago JG123 513

0

votes

0

answers

11

views

locally Euclidean of manifold

differential-geometry manifolds solution-verification smooth-manifolds

modified 1 hour ago yi_li 477

6

votes

1

answer

90

views

$\lim\limits_{n \to\infty}\sqrt[n]{\{\sqrt{2}\}\{2\sqrt{2}\}\{3\sqrt{2}\}\cdot\cdot \cdot \cdot \{n\sqrt{2}\} } $

real-analysis calculus limits uniform-distribution ergodic-theory

modified 1 hour ago John Mars 288

0

votes

0

answers

8

views

Proof of Cartan Theorem B in Hörmander's book

complex-geometry several-complex-variables

asked 1 hour ago Colescu 6,844

-3

votes

0

answers

14

views

how to show the question in the below picture is a banach space

functional-analysis functions partial-differential-equations sobolev-spaces banach-algebras

asked 1 hour ago A Rahman 1

0

votes

0

answers

12

views

Finite Geometry Properties

geometry solution-verification noneuclidean-geometry

modified 1 hour ago Burt 1,484

1

vote

1

answer

27

views

Can a single point uniquely determine the whole semi-group?

functional-analysis operator-theory semigroup-of-operators

answered 1 hour ago DisintegratingByParts 68.6k

0

votes

2

answers

24

views

How to prove two separate curves make a circle

geometry circles parametric covering-spaces

answered 1 hour ago zkutch 3,904

1

vote

1

answer

14

views

Identifying a Better Estimator for the Three Day Average

probability-distributions estimation

answered 1 hour ago Lucas Resende 818

1

vote

1

answer

23

views

Let $A \rightarrow B$ be etale. Is multiplication $B \rightarrow B \otimes_A B$ faithfully flat?

algebraic-geometry commutative-algebra etale-cohomology

modified 1 hour ago Stahl 19.3k

-2

votes

0

answers

13

views

Matching liabilities and assets (SOA Exam FM)

actuarial-science

modified 1 hour ago confused_donkey 1

0

votes

0

answers

8

views

Infinitely differentiable approximations for an indicator function

calculus approximation

asked 1 hour ago qp212223 622

0

votes

0

answers

25

views

If $f$ is differentiable in $B(a)$ , so $\nabla f=0 \implies f=\text{constant}$ and $f(x)\leq f(a) \implies \nabla f(a)=0$.

real-analysis multivariable-calculus

modified 1 hour ago sai-kartik 1,722

0

votes

1

answer

18

views

Probability formulas

probability solution-verification

modified 1 hour ago Burt 1,484

1

vote

1

answer

18

views

Minimizer of $\mathbb{E}\left[\left( g(\Theta) - \delta(X) \right)^2 | X \right]$

statistical-inference conditional-expectation

modified 1 hour ago triple_sec 19.7k

0

votes

1

answer

16

views

In the infinite Cartesian product in Enderton's Elements, how is $H$ a function if $H(i)$ has multiple elements?

elementary-set-theory

answered 1 hour ago Brian M. Scott 513k

1

vote

0

answers

29

views

Upper bound in bayesian regression setting

probability inequality norm matrix-decomposition upper-lower-bounds

modified 1 hour ago Dushyant Sahoo 161

1

vote

1

answer

34

views

What is the function $f$ verifying $f\left(\frac{x}{2}+\frac{x}{2}\cos\left(\frac{v\pi}{x}\right)\right)=\frac{x}{2}\sin\left(\frac{v\pi}{x}\right)$?

functions functional-equations

modified 1 hour ago Mohsen Shahriari 3,753

0

votes

1

answer

22

views

Probability function of $T=Y-X$

probability statistics

modified 1 hour ago Graham Kemp 103k

0

votes

1

answer

20

views

Find closest distribution to minimize KL divergence

optimization lagrange-multiplier information-theory

answered 1 hour ago kodlu 4,197

2

votes

1

answer

38

views

Judge the convergence of this integral $\int_{0}^{1} \frac{\sqrt[m]{\ln ^{2}(1-x)}}{\sqrt[n]{x}} d x$

limits convergence-divergence

modified 1 hour ago Danny Pak-Keung Chan 5,323

0

votes

0

answers

20

views

Prove that $E(t)=\int\limits^L_0h^2(x)+(g'(x))^2+(g''(x))^2+(g'''(x))^2dx$

calculus integration partial-differential-equations

modified 1 hour ago gune 1,044

8

votes

0

answers

174

views

Cleverly showing that $\lim_{x\to 0}\frac{x^{(\sin x)^x}-(\sin x)^{x^{\sin x}}}{x^3}=\frac{1}{6}$

calculus limits

modified 1 hour ago Please correct GrammarMistakes 299

2

votes

1

answer

52

views

Finding the explicit formula given recursion

recurrence-relations

answered 1 hour ago vonbrand 24.4k

0

votes

0

answers

26

views

Given $X \in \mathbb{R}$ and $Y\in \{0,1\}$, is there a simple expression for $\dfrac{1}{1+e^{-(X+Y)}}- \dfrac{1}{1+e^{-X}}$?

functions

modified 1 hour ago janmarqz 7,377

1

vote

1

answer

33

views

Convergence of $E[N/Q \mid Q>0]$ when $Q \sim B(N,p)$

probability statistics conditional-expectation

modified 2 hours ago RobPratt 13.9k

0

votes

1

answer

21

views

Showing that the graph of a continuous linear mapping is closed if the domain is closed

functional-analysis continuity linear-transformations normed-spaces closed-graph

answered 2 hours ago Zeta-Squared 780

0

votes

1

answer

17

views

Are fractional derivatives defined analogously for a complex parameter?

complex-analysis analytic-continuation fractional-calculus

answered 2 hours ago Simply Beautiful Art 67.1k

0

votes

0

answers

8

views

I struggle to sketch 3D concepts, looking for 2D analogs that might help

visualization

asked 2 hours ago Nicholas Montaño 139

4

votes

1

answer

35

views

Relationship between the ideal of an effective Cartier divisor and its invertible sheaf

algebraic-geometry sheaf-theory schemes divisors-algebraic-geometry line-bundles

modified 2 hours ago Stahl 19.3k

0

votes

0

answers

16

views

Directional derivatives problem with a sphere $x^2+y^2+z^2 = R^2$ at the point $(0,0,R)$

calculus multivariable-calculus vector-analysis

modified 2 hours ago GohP.iHan 969

0

votes

0

answers

7

views

Determining a meromorphic function by its poles.

residue-calculus cauchy-integral-formula meromorphic-functions weierstrass-factorization

modified 2 hours ago Dr Potato 517

0

votes

1

answer

6

views

How to select the columns of a binary feature matrix to obtain minimal overlap

optimization

answered 2 hours ago RobPratt 13.9k

0

votes

0

answers

26

views

Lemma for Fundamental Theorem of Finite Abelian Groups

abstract-algebra group-theory abelian-groups

modified 2 hours ago Cup 91

0

votes

0

answers

15

views

Lagrangian as a function on tangent bundle

smooth-manifolds classical-mechanics tangent-bundle

modified 2 hours ago User1610788 1

0

votes

1

answer

19

views

Prove two random variables are equal almost everywhere

probability-theory random-variables

answered 2 hours ago bitesizebo 3,009

1

vote

1

answer

19

views

Some steps in Jech's presentation of Solovay-Tennenbaum Theorem

set-theory forcing

answered 2 hours ago Reveillark 9,845

1

vote

1

answer

7

views

Division of a Convex Shape results in a Convex Shape

geometry plane-geometry convex-geometry convex-hulls

answered 2 hours ago Robert Israel 386k

4

votes

1

answer

56

views

+50

Random walks and finiteness of a sum

probability-theory stochastic-processes random-walk

answered 2 hours ago Ravi Fernando 2,366

0

votes

0

answers

5

views

Show that $u(0,y+h)\leq(1+\frac{h}{y-h})^nu(0,y)$ for all $0<h<y$ for harmonic $u$

partial-differential-equations

modified 2 hours ago gune 1,044

1

vote

1

answer

51

views

Show that $c=\det f$ with $f: V \to V$ is a linear transformation.

analysis determinant tensor-products tensors dual-maps

modified 2 hours ago Azif00 9,924

0

votes

0

answers

19

views

The relation between eigenvalues, row operations, and column space

linear-algebra

asked 2 hours ago Weizi Li 27

0

votes

0

answers

7

views

Concentration for Markov process with known expectation and variance?

probability markov-process variance concentration-of-measure

asked 2 hours ago Brendan Mallery 45

2

votes

0

answers

29

views

Is every extreme probability on a countably generated space a point mass?

probability-theory measure-theory solution-verification

modified 3 hours ago grndl 6,722

2

votes

1

answer

19

views

Application of Birkhoff Ergodic Theorem; Asymptotic direction of shortest geodesics at a fixed point in Riemannian manifold

riemannian-geometry ergodic-theory

answered 3 hours ago John B 14.1k

2

votes

1

answer

54

views

Intuition behind Scott sentences

logic model-theory

modified 3 hours ago hermes 14.6k

0

votes

0

answers

7

views

Presburger Arithemtic and Cooper's Algorithm

arithmetic quantifier-elimination presburger-arithmetic

asked 3 hours ago Astronought 101

2

votes

0

answers

14

views

Removing egdes connecting a vertex with vertices of higher (or same) degree

graph-theory

modified 3 hours ago liaombro 1,926

0

votes

0

answers

8

views

Semisimple subgroup of Euclidean group

lie-groups lie-algebras

asked 3 hours ago Totoro 693

0

votes

0

answers

14

views

Equations over finite fields to prove primality

group-theory prime-numbers finite-groups finite-fields multiplicative-order

asked 3 hours ago J. Linne 2,148

5

votes

0

answers

44

views

Intuition behind sums of sums of whole numbers

combinatorics summation binomial-coefficients recreational-mathematics intuition

modified 3 hours ago RobPratt 13.9k

1

vote

0

answers

23

views

An abelian group $G$ that has order 216, but $6G$ has order 6

abstract-algebra group-theory finite-groups abelian-groups

modified 3 hours ago Shaun 23.9k

1

vote

1

answer

16

views

Understanding a result regarding subgroups containing the $n$-th powers of a field as a subgroup of finite index

abstract-algebra group-theory field-theory galois-theory

answered 3 hours ago Ravi Fernando 2,366

1

vote

2

answers

88

views

Proof of Fubini's Theorem for Series

real-analysis sequences-and-series analysis self-learning

answered 3 hours ago Kareem Taha 43

0

votes

0

answers

11

views

principal value on semi-infinite interval

fourier-transform dirac-delta

modified 3 hours ago Mohsen Shahriari 3,753

0

votes

0

answers

5

views

Wernick's list problem number 27: $A,M_a,I$ find vertexes $B$ and $C$

geometry euclidean-geometry geometric-construction

asked 3 hours ago hellofriends 235

2

votes

1

answer

31

views

Prove that $\Phi$ is not onto and $\Phi^{-1}$ is continuous (Structure Theorem for Distributions)

functional-analysis distribution-theory topological-vector-spaces

answered 4 hours ago KeeperOfSecrets 656

2

votes

4

answers

7k

views

Method of False Position (Regular Falsi) - Pros/Cons

numerical-methods

answered 4 hours ago Simply Beautiful Art 67.1k

0

votes

0

answers

14

views

If $S\subseteq\Bbb R^n$ is compact and rectifiable then $\pi_{\Bbb R^m}[S]$ is rectifiable too for any $m< n$.

integration general-topology measure-theory riemann-integration

modified 4 hours ago Bernard 153k

0

votes

0

answers

11

views

How do I compare these two statistical PDFs to see which is more likely to be bigger than the other?

probability statistics probability-distributions uniform-distribution

asked 4 hours ago shurup 229

0

votes

0

answers

24

views

A hyperplane $W$ of a symplectic vector space $V$ is coisotropic.

solution-verification differential-forms symplectic-geometry symplectic-linear-algebra

modified 5 hours ago eightc 59

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