KarL05's Blog
Inequality Revision 1

Inequalitys with multi variables

Cauchy

\[ \sum_{i=1}^n(a_i^2)\sum_{i=1}^n(b_i^2)\geq \sum_{i=1}^n (a_i b_i)^2\]

Carlson

k = 2 is Cauchy

k is the number of lists.

\[ \sum_{i=1}^n(a_i^k)\sum_{i=1}^n(b_i^k)...\sum_{i=1}^n(z_i^k)\geq \sum_{i=1}^n (a_i b_ic_i...z_i)^k\]

Jensen

can be weighed

concave

\[ f(\frac{\sum_{i=1}^n x_i}{n}) \geq \sum_{i=1}^n\frac{f(x_i)}{n}\]

convex

\[ f(\frac{\sum_{i=1}^n x_i}{n}) \leq \sum_{i=1}^n\frac{f(x_i)}{n}\]

Holder

\(\frac{1}{p} + \frac{1}{q} = 1\), \(p = q = 2\) is Cauchy

\[ \sum_{i=1}^n(a_i^p)^q\sum_{i=1}^n(b_i^q)^p\geq \sum_{i=1}^n (a_i b_i)^{pq}\]

AM-GM

Define

\[ D(p) = \lim_{k \to p}(\frac{x_i^k}{n})^{\frac{1}{k}}\]

Then

QM AM GM HM Rule

\[ D(2) \geq D(1) \geq D(0) \geq D(-1)\]