Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

This is a notational question:

What does $\overset{\underset{\mathrm{\Delta }}{}}{=}$ denote in

$-0.5JDJ\overset{\underset{\mathrm{\Delta }}{}}{=} X^TX$ where $J=I-n^{-1}ee^T$ with $e$ being a vector of $1's$ and $D$ is a matrix of squared distances of the rows in $X$ i.e, $D_{ij}=||X_{i.}-X_{j.}||^2$

share|improve this question
add comment

1 Answer

up vote 1 down vote accepted

The symbol usually means 'is defined as' or 'is another name for'. Do you see why that might make sense in your context?

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.