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ryang
  • Member for 10 years, 6 months
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25 votes
2 answers
3k views

Proof that no permutation can be expressed both as the product of an even number of transpositions and as a product of an odd number of transpositions

19 votes
1 answer
26k views

The definition of locally Lipschitz

18 votes
3 answers
26k views

Relationship between cross product and outer product

14 votes
2 answers
473 views

An inequality from Littlewood's Miscellany

12 votes
1 answer
11k views

A non-square matrix with orthonormal columns

10 votes
2 answers
6k views

Relation between Interior Product, Inner Product, Exterior Product, Outer Product

10 votes
2 answers
22k views

Are a square matrix's columns and rows either both(separately) linearly independent or both(separately) linearly dependent?

10 votes
3 answers
63k views

Given a matrix A, how to find B such that AB=BA [duplicate]

10 votes
3 answers
2k views

Can the the radius of convergence increase due to composition of two power series?

10 votes
3 answers
5k views

Confused by Laurent series

9 votes
3 answers
1k views

$f$ is integrable but has no indefinite integral

8 votes
5 answers
2k views

Help understanding why a block code can correct up to (d-1)/2 errors.

8 votes
3 answers
3k views

Are undefined terms allowed in a sequence?

8 votes
1 answer
3k views

Drawing by lifting pencil from paper can still beget continuous function.

8 votes
1 answer
331 views

Is $(-\infty,\infty)$ a closed **interval**?

7 votes
1 answer
1k views

Abuse of big-O notation? (version 2 - simplified and revised)

7 votes
3 answers
7k views

Why is it that a linear transformation can only preserve or reduce a vector space's dimension?

7 votes
4 answers
2k views

Why is it meaningless for a closed set to be polygonal path connected?

6 votes
1 answer
5k views

Non-binary Hamming codes?

6 votes
2 answers
5k views

Proof of the "Radius of Convergence Theorem"

6 votes
1 answer
17k views

Fourier series for $\sin x$ is zero?

6 votes
2 answers
5k views

Composing two discontinuous functions into a continuous one

6 votes
1 answer
3k views

Rigorous proof of the "Lagrange-multiplier theorem"

6 votes
1 answer
2k views

Is a Bernoulli process a Markov chain?

5 votes
1 answer
225 views

Finding a common subsequence given two sequences on the same elements

5 votes
2 answers
718 views

$(0 \leq f' \leq f$ on $\mathbb R$ and $f(a)=0)$ $\implies f=0$?

5 votes
2 answers
311 views

Dartboard paradox and understanding independence

5 votes
4 answers
620 views

Another simple series convergence question: $\sum\limits_{n=3}^\infty \frac1{n (\ln n)\ln(\ln n)}$

5 votes
1 answer
619 views

Writing "$\nabla f$" or "$\operatorname{grad} f$"

5 votes
4 answers
1k views

Determining isomorphism of graphs

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