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51 votes
2 answers
5k views

A strengthening of the Cauchy-Schwarz inequality

Suppose $\mathbf{v},\mathbf{w} \in \mathbb{R}^n$ (and if it helps, you can assume they each have non-negative entries), and let $\mathbf{v}^2,\mathbf{w}^2$ denote the vectors whose entries are the ...
Nathaniel Johnston's user avatar
13 votes
1 answer
1k views

An inequality for the spectral radius of matrices used by J. Bochi

I am interested in the history of an inequality for the spectral radius of a $d\times d$ real or complex matrix, which occurs in Jairo Bochi's 2002 article Inequalities for numerical invariants of ...
Ian Morris's user avatar
  • 6,206
8 votes
1 answer
485 views

An inequality related to Riesz–Thorin theorem, determinants and $L_p$ norm

Let $a, b, c \in \mathbb{R}^n$ , $p \in [1, +\infty)$, prove that $$\left( \sum_{1\leq i < j <k \leq n} \left| \det\left(\begin{matrix} a_i & b_i & c_i \\ a_j & b_j & c_j \\ ...
Chen Dan's user avatar
  • 563
5 votes
1 answer
332 views

On a certain norm of the identity operator on $\mathbb R^2$

$\newcommand\R{\mathbb R}\newcommand\Q{\mathcal Q}$For mutually orthogonal vectors unit vectors $a=[a_1,\dots,a_n]^T$ and $b=[b_1,\dots,b_n]^T$ in $\R^n=\R^{n\times1}$ (so that $n\ge2$) and for all $x=...
Iosif Pinelis's user avatar