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peter
  • Member for 8 years, 1 month
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2 votes
1 answer
39 views

Two spaces contain the same vector, can we say the space with smaller dimension is a subspace of the larger one?

2 votes
3 answers
131 views

How to simply the sum $\sum\limits_{k=1}^n\frac{N-n+k}{(N-k+1)(N-k+1)(N-k)}$?

2 votes
2 answers
84 views

Whether is there a bound of $\sigma^2$ such that $pe^t+qe^{-t}\leq e^{t^2\sigma^2/2}$?

2 votes
1 answer
42 views

How to prove :For $a_i\in(0,1)$ ($i=1,\cdots,N$), then $\prod\limits_{i=1}^Na_i+\prod\limits_{i=1}^N\sqrt{1-a_i^2}\leq1.$

1 vote
0 answers
34 views

Express the operator of a tensor product by a form containing an inner product term

1 vote
0 answers
22 views

The cardinal number of a net of $l_2$ unit ball in $\mathcal{R}^n$

1 vote
1 answer
46 views

Is there an upper bound about the probability $\mathcal{P}(\|Ax\|_{\infty}\geq t)$

1 vote
0 answers
50 views

Is there any clue for the supremum of projective norm in an unit ball of injective tensor product space

1 vote
1 answer
102 views

Is the inner product of matrices invariant under rotation?

1 vote
3 answers
246 views

Is one projection which preserves norm is identity?

1 vote
0 answers
240 views

How to prove tensor product of orthogonal projections is still orthogonal ?

1 vote
0 answers
38 views

Does the following inequality hold? $\sum\limits_{i=1}^a\sum\limits_{j=1}^b\sum\limits_{k=1}^c|A_iB_jC_k|\leq 1$ as $||A||=||B||=||C||=1$

1 vote
0 answers
58 views

Uniqueness of minimizer of the vector 1-norm of $QM$ over all real orthogonal matrices $Q$

0 votes
2 answers
33 views

Proof a vector only contains -1, 0 and 1 under condition $\sum\limits_{i=1}^nv_i^2=\sum\limits_{i=1}^n|v_i|$

0 votes
1 answer
28 views

Whether two matrices $M_1$ and $M_2$ are the same, that their entry-wise sums are the same and $M_2=UM_1V$ , where $U$, $V$ are both othogonal

0 votes
1 answer
2k views

What is the variance proxy of a such sub-Gaussian random variable

0 votes
1 answer
46 views

How to get the number of all possible combinations of k positive integers to reach a given product?

0 votes
1 answer
50 views

How to prove $E\|Y'\|\leq E\|Y'-Y''\|,$ where $Y$ is a random matrix in $\mathbb{R}^{n\times n}$, and $Y'$, $Y''$ are independent copies of $Y$?