-2

I was reading about k-strong convexity and came a across an equation like this

f(x_1) >= f(x_2) + <\Delta f(x_2), x_1-x_2> + (k/2)*(||x_1-x_2||^2)

Could some one explain what the notation <> means?

Sorry for the errors with latex.

krishna
  • 405
  • 6
  • 25
  • is a dot product. Exact equation depends on the particular dot product, but the most common one is SUM_i x_i y_i – lejlot Oct 23 '16 at 23:14
  • I'm voting to close this question as off-topic because it doesn't cover any topics relevant to this site (as described in the [site tour](http://stackoverflow.com/tour)). – Werner Oct 25 '16 at 06:32

2 Answers2

1
<x,y> is the dot (scalar) product of x and y 

<x,y> = y'*x

as y' is the tronspose of y, for more you can cheek scalar product

Bilal
  • 11
  • 1
  • 5
-2

I think that these part of quantum mechanics, especially matrix mechanics < x1 is called bra vector and x2> is called as the ket vector. Please check with quantum mechanics book. Please check the book by Dirac on quantum mechanics.

vaman
  • 28
  • 2