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2

votes

1

answer

27

views

Do Approximate Eigenvalues Imply Approximate Eigenvectors?

linear-algebra matrices eigenvalues-eigenvectors symmetric-matrices perturbation-theory

modified 1 min ago copper.hat 146k

2

votes

2

answers

26

views

$L = \lim \limits_{T\to \infty} \frac{1}{T}\int \limits_{-T/2}^{T/2} cos(\omega t + \theta)~dt$

calculus limits

answered 2 mins ago cjferes 1,594

0

votes

0

answers

9

views

For any two positive elements $a,b$ with norm $<1$ there is a $c$ such that $a,b\leq c$ and $\|c\|<1$. Does this hold for $\|a\|=\|b\|=1$?

operator-theory hilbert-spaces c-star-algebras banach-algebras

modified 2 mins ago Sui 11

1

vote

3

answers

16

views

A is greater than B by 25% then by what percentage B is less than A?

percentages

answered 3 mins ago Ethan Bolker 65.1k

1

vote

1

answer

12

views

Soft-EM: E-step for fitting mixed linear regression model

statistics machine-learning linear-regression

modified 5 mins ago Kenny Wong 22.2k

2

votes

1

answer

26

views

Series going to $+\infty$

real-analysis calculus sequences-and-series

modified 5 mins ago Robert890 121

0

votes

0

answers

13

views

Show continuity of partial derivatives of piece-wise function

calculus multivariable-calculus derivatives partial-derivative

asked 8 mins ago learning_linalg 71

5

votes

1

answer

23

views

Solving $ 2(2^x- 1) x^2 + (2^{x^2}-2)x = 2^{x+1} -2$

algebra-precalculus exponential-function roots

modified 8 mins ago Michael Rozenberg 158k

0

votes

0

answers

7

views

Picking the set of coset representatives of a stabilizer under a group action

group-theory finite-groups symmetric-groups group-actions

modified 8 mins ago Shaun 23.6k

0

votes

1

answer

17

views

Understanding the $\alpha$ existence in the definition of the boundary map in case of simplicial homology and its absence in singular homology.

algebraic-topology definition homology-cohomology homological-algebra group-cohomology

modified 9 mins ago SeraPhim 565

0

votes

0

answers

6

views

Prove $D(A):= \{w\in H^{2}(0, 2\pi): w(0) = w(2\pi), w^{'}(0) = w^{'}(2\pi) \}$ is dense in $L^{2}(0,2\pi).$

functional-analysis metric-spaces

asked 14 mins ago John M-D94 131

0

votes

1

answer

27

views

Does there exist a function which is real-valued, non-negative and bandlimited?

analysis fourier-analysis harmonic-analysis

answered 15 mins ago Kavi Rama Murthy 203k

0

votes

0

answers

5

views

How to segment a group of symmetric points

geometry

asked 15 mins ago Khaled 1

0

votes

2

answers

19

views

Is this a valid strategy to find group new group automorphisms given you already know some?

abstract-algebra automorphism-group

answered 16 mins ago David Craven 1,353

1

vote

0

answers

15

views

Proving that $f + g, f \cdot g$, and $f/g$ are continuous using neighborhoods

general-topology continuity real-numbers

asked 17 mins ago Novice 305

0

votes

0

answers

3

views

Embedded submanifolds satisfy local slice criterion

differential-geometry differential-topology

asked 18 mins ago Victor 83

1

vote

0

answers

5

views

Symplectomorphism and Hodge decomposition

complex-geometry symplectic-geometry de-rham-cohomology

asked 19 mins ago curious math guy 727

1

vote

0

answers

84

views

What is the value of $\int_{0}^{t} (t-s)^{\alpha-1} (1-s)^{\alpha} \rm{d}s$?

integration gamma-function fractional-calculus

modified 20 mins ago logo 962

3

votes

1

answer

31

views

Linearized system for $ \begin{cases} \frac{d}{dt} x_1 = -x_1 + x_2 \\ \frac{d}{dt} x_2 = x_1 - x_2^3 \end{cases} $ is not resting at rest point?

ordinary-differential-equations numerical-methods dynamical-systems control-theory linearization

modified 21 mins ago Batominovski 46.1k

-2

votes

0

answers

14

views

How do I know if i have solved graph isomorphism problem?

graph-isomorphism

asked 22 mins ago mark.smith63 1

4

votes

2

answers

51

views

Why is $\lambda$ called the instantaneous rate of change in the exponential distribution?

probability markov-chains intuition exponential-distribution poisson-process

answered 23 mins ago Math1000 29.2k

0

votes

0

answers

9

views

Write condition if rectangle is inside another rectangle

geometry

asked 23 mins ago Lenny White 227

0

votes

0

answers

16

views

Constraints on $x^2 + b x + c = 0$ such that at least one root has a positive real part

complex-numbers determinant roots quadratics

modified 23 mins ago kevinkayaks 313

0

votes

1

answer

11

views

Why does this not satisfy the conditions of a metric?

metric-spaces

answered 23 mins ago Brian M. Scott 508k

2

votes

1

answer

1k

views

To prove how limit exists using definition given.

complex-analysis limits

modified 29 mins ago Community♦ 1

0

votes

0

answers

12

views

probability question related to sensors?

probability

asked 31 mins ago peeps 1

2

votes

1

answer

736

views

Not getting surface integrals

calculus multivariable-calculus surface-integrals

modified 36 mins ago Integrand 5,676

0

votes

0

answers

10

views

Smooth manifold and $f: X → \mathbb{R}$ to be a derivative of order n

differential-geometry algebraic-topology differential-topology geometric-topology

modified 37 mins ago Integrand 5,676

1

vote

1

answer

38

views

Differential of a mapping misnomer

calculus differential-geometry

modified 40 mins ago Zohar Levi 111

0

votes

1

answer

7

views

What are some (“small”) Riesel numbers without a covering set?

elementary-number-theory prime-numbers covering-sets

answered 42 mins ago Jeppe Stig Nielsen 4,361

23

votes

18

answers

6k

views

Zeno's Achilles & Tortoise - Where exactly is the proof wrong?

sequences-and-series infinity paradoxes

modified 42 mins ago Paul Frost 30.5k

1

vote

1

answer

16

views

Probability of the average lifetime of $n$ machines

probability probability-distributions

answered 42 mins ago Alex 17.1k

1

vote

1

answer

54

views

Is this probabilistic proof for Brocard's Conjecture flawed?

elementary-number-theory prime-numbers solution-verification square-numbers conjectures

answered 46 mins ago Maxim Enis 23

1

vote

0

answers

43

views

Fibonacci mod prime $5k \pm 1$

number-theory prime-numbers fibonacci-numbers

modified 48 mins ago Integrand 5,676

0

votes

0

answers

14

views

Independence of events in Bernoulli Probability Space

probability measure-theory

modified 48 mins ago user1333549 5

0

votes

0

answers

14

views

Laplace transform of a modified generalised logistic function

functions laplace-transform

modified 49 mins ago mjw 3,091

5

votes

2

answers

64

views

Is there a function that grows slower than the factorial function and whose derivative grows faster than the function itself?

calculus limits functions derivatives factorial

answered 51 mins ago Rivers McForge 842

1

vote

1

answer

187

views

Kürschák 2018, Problem 2: Vectors in the $3$-dimensional space with integer coordinates.

geometry elementary-number-theory prime-numbers contest-math coordinate-systems

modified 53 mins ago Batominovski 46.1k

0

votes

0

answers

12

views

Vector bundle nonvanishing section

general-topology manifolds differential-topology

modified 54 mins ago Luka 427

1

vote

1

answer

44

views

Discussion of continuous functions in topology

real-analysis general-topology analysis continuity metric-spaces

answered 57 mins ago Brian M. Scott 508k

0

votes

1

answer

14

views

Painting the edges of an $n$-gonal prism with 3 colors all the edges of each vertex have different colors if $n= 2018$ and $n= 2019$?

graph-theory

modified 59 mins ago Ross Millikan 340k

0

votes

0

answers

4

views

Is there an ordering of two points in a plane that is stable against small perturbations? / unique parameterization for line segments?

geometry

asked 1 hour ago Doug Reeder 101

1

vote

2

answers

31

views

Detecting if objects are at opposite coordinates

geometry coordinate-systems

answered 1 hour ago miracle173 8,400

1

vote

0

answers

15

views

Term for 3D Surface Mapped into 2D Plane

geometry differential-geometry terminology

modified 1 hour ago Mark S. 14.8k

0

votes

1

answer

18

views

Uncertainty of a Weighted Mean with Uncertain Weights

standard-deviation means error-propagation

modified 1 hour ago Ian 78.8k

1

vote

1

answer

27

views

Transient, Positive Recurrent, or Null Recurrent

probability statistics markov-chains

modified 1 hour ago Math1000 29.2k

3

votes

1

answer

61

views

In infinite dimensions, is it possible that convergence of distances to a sequence always implies convergence of that sequence?

metric-spaces banach-spaces normed-spaces cauchy-sequences

modified 1 hour ago Nikhil Sahoo 556

0

votes

0

answers

38

views

Is this graphing calculator broken, or is this someting really weird?

chaos-theory

modified 1 hour ago Henry 118k

6

votes

1

answer

96

views

Proving $\log\left(\frac{4^n}{\sqrt{2n+1}{2n\choose n+m}}\right)\geq \frac{m^2}{n}$

combinatorics inequality logarithms combinatorial-proofs

modified 1 hour ago Blue 59.2k

2

votes

1

answer

22

views

Injection from $(K\otimes_{\mathbb{Z}}\hat{\mathbb{Z}})^\to \prod_p(K\otimes_{\mathbb{Z}}\mathbb{Z}_p)^$?

algebraic-number-theory tensor-products class-field-theory profinite-groups

answered 1 hour ago WhatsUp 9,876

1

vote

1

answer

39

views

Proving continuity at the end points of the extension of a continuous function

real-analysis general-topology proof-writing solution-verification

modified 1 hour ago Ricky_Nelson 845

0

votes

1

answer

28

views

Lebesgue Measure Space and a converging, increasing sequence. Show that the sequence in increasing.

measure-theory lebesgue-measure

modified 1 hour ago amWhy 198k

-1

votes

0

answers

12

views

Determine Whether a Metric is Separable, Complete,or Compact

metric-spaces

modified 1 hour ago N. Bar 1,334

11

votes

1

answer

1k

views

Classification of triply transitive finite groups

group-theory finite-groups permutations

modified 1 hour ago Community♦ 1

0

votes

1

answer

25

views

Are chain complexes chain equivalent to free ones?

homological-algebra

answered 1 hour ago Yuta 43

0

votes

0

answers

12

views

Uniqueness of measures related to the Stieltjes transforms

measure-theory moment-problem

asked 1 hour ago James 185

2

votes

0

answers

34

views

How do you take the derivative $\frac{d}{dx} \int_a^x f(x,t) dt$?

calculus integration derivatives

asked 1 hour ago Zachary Feng 115

2

votes

0

answers

14

views

References on tetrahedra

reference-request

modified 1 hour ago Alo 33

1

vote

1

answer

16

views

Neyman–Pearson Lemma

statistics hypothesis-testing

modified 1 hour ago Michael Hardy 237k

12

votes

0

answers

51

views

The complexity of finiteness

logic set-theory model-theory axiom-of-choice second-order-logic

modified 1 hour ago Noah Schweber 169k

0

votes

0

answers

6

views

Questions about GSADF and BASDF test's parameters

statistics regression programming

asked 1 hour ago Diricksen 1

7

votes

0

answers

210

views

+100

Discretization formula for system of two differential equations. “Solution to one of these is the initial condition of the other”. In which sense?

ordinary-differential-equations probability-theory numerical-methods stochastic-differential-equations numerical-calculus

modified 1 hour ago Strictly_increasing 317

0

votes

1

answer

14

views

Time Average Mean of X(t)=A, where A is a r.v. Ergodic vs. non-ergodic.

stochastic-processes

answered 1 hour ago pico 469

2

votes

1

answer

21

views

Prove/disprove that $ \mathbb{R}^2 / $~ is hausdorff, when: $(x_1,x_2) $~$(y_1,y_2)$ if there is $t>0$ such that $x_2 = tx_1 $ and $ty_2 = y_1$

general-topology quotient-spaces hausdorff-measure

modified 1 hour ago Vercassivelaunos 1,148

0

votes

0

answers

10

views

Numerical differentation - finding maxima

derivatives numerical-methods maxima-minima

asked 1 hour ago Leif 1,335

0

votes

0

answers

15

views

The name of a problem from formal language theory

algorithms formal-languages

asked 1 hour ago Elmar Guseinov 503

0

votes

0

answers

18

views

Problem computing integral of a 2D gaussian ring

integration gaussian-integral python gaussian

modified 2 hours ago Julien Drevon 1

-1

votes

0

answers

8

views

Find proper subsets as set coverings with coefficients

combinatorics combinatorial-proofs

asked 2 hours ago zxclkjqwe 1

5

votes

2

answers

192

views

What is the derivative of $\log \det X$ when $X$ is symmetric?

matrices derivatives determinant

answered 2 hours ago Alex Williams 248

5

votes

0

answers

41

views

Lie group theory's connection to fractional calculus?

lie-groups fractional-calculus

modified 2 hours ago jnez71 3,469

1

vote

0

answers

7

views

What are evaluation metrics for regression-type neural net?

machine-learning regression neural-networks error-function mean-square-error

asked 2 hours ago Capo Pavel Mestre 127

0

votes

0

answers

14

views

Piecewise regular curves

real-analysis

asked 2 hours ago Leonardo 1

1

vote

1

answer

21

views

Special Case of Independence for Joint Densities

probability probability-theory discrete-mathematics probability-distributions proof-explanation

answered 2 hours ago Robert Israel 383k

0

votes

0

answers

12

views

Conversion of relative pitch and yaw angle to screen coordinates

transformation

modified 2 hours ago Xander Henderson 20k

1

vote

2

answers

21

views

Find ideal, char and subring

abstract-algebra ring-theory ideals characteristics

answered 2 hours ago k.stm 15.8k

1

vote

0

answers

29

views

Is there a specific name for this geometrical shape?

geometry terminology

asked 2 hours ago Neeku 111

3

votes

1

answer

28

views

Center of of a subalgebra of a lie algebra: Under what conditions is $Z(\mathfrak{h})=Z(\mathfrak{g})\cap \mathfrak{h}$

abstract-algebra lie-algebras semisimple-lie-algebras

answered 2 hours ago Torsten Schoeneberg 10.8k

-1

votes

0

answers

6

views

Solving a functional equation (in 2D)

functional-analysis functional-equations functional-calculus

asked 2 hours ago sara nj 288

2

votes

0

answers

35

views

Formulas for the Spinor Representation Product Decompositions $2^{[\frac{N-1}{2}]} \otimes 2^{[\frac{N-1}{2}]}=?$ and …

group-theory differential-geometry representation-theory lie-groups spin-geometry

modified 2 hours ago wonderich 4,675

0

votes

0

answers

12

views

Relatively compact set in $l_1$

functional-analysis

asked 2 hours ago 2132123 854

0

votes

1

answer

14

views

Solution to autonomous differential equation with locally lipscitz function

ordinary-differential-equations lipschitz-functions fundamental-solution

modified 2 hours ago user1551 97.6k

0

votes

0

answers

12

views

Time Series Normalization & Where to Start

regression time-series

asked 2 hours ago FamousAv8er 101

0

votes

0

answers

12

views

Can closed forms for the outputs in this production simulation be found?

elementary-number-theory modular-arithmetic ceiling-and-floor-functions simulation

asked 3 hours ago SmallestUncomputableNumber 1,439

1

vote

0

answers

27

views

Maximizing the Leontief inverse

linear-algebra optimization convex-optimization inverse nonlinear-optimization

modified 3 hours ago user_lambda 936

0

votes

0

answers

13

views

Is this injective projection map open?

differential-geometry algebraic-geometry complex-geometry

asked 3 hours ago Longma 1

0

votes

0

answers

13

views

How to impose constraint on quadratic equation fit based on their parameters?

quadratics regression python

modified 3 hours ago RobPratt 13.7k

1

vote

0

answers

17

views

Number of events in a series of Poisson processes?

probability poisson-process

modified 3 hours ago RobPratt 13.7k

0

votes

1

answer

25

views

Inverting product of non-square matrices?

linear-algebra matrices inverse

modified 3 hours ago Rodrigo de Azevedo 15.7k

0

votes

0

answers

14

views

Proof of continuity of paramtric integral via sequences

real-analysis integration analysis continuity

modified 3 hours ago Philipp 964

1

vote

0

answers

48

views

Clarification on theorem 5.4 in John Conway book on Complex analysis

complex-analysis complex-integration cauchy-integral-formula

modified 3 hours ago Cloud JR 2,077

0

votes

0

answers

15

views

How to check if a differential operator is translation invariant practically?

differential-geometry greens-function

asked 3 hours ago Lelouch 726

3

votes

0

answers

34

views

Why is it called the “sampling distribution of the mean”?

statistics descriptive-statistics

modified 3 hours ago JCAA 4,525

0

votes

0

answers

12

views

Homology of infinite Koszul complex tensored with an injective module vanishes

abstract-algebra homology-cohomology homological-algebra

asked 4 hours ago Ivon 811

2

votes

0

answers

20

views

Containment of Bruhat cells on flag variety

algebraic-geometry algebraic-groups

modified 4 hours ago Qixian Zhao 153

5

votes

0

answers

55

views

Second cohomology group of an affine Lie algebra

representation-theory lie-algebras group-cohomology

modified 4 hours ago B. Pasternak 1,728

3

votes

0

answers

22

views

Is it true that if $P(\int_0^T f^2(s) ds<\infty)=1$ then the exponential defines a density?

probability stochastic-processes stochastic-calculus stochastic-analysis

asked 4 hours ago user658409 1,272

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