Talk:Positive-definite function on a group

Algebraic groups
The introduction says a positive-definite function on a group relates the notions of positivity, in the context of Hilbert spaces, and algebraic groups. Unfortunately, "algebraic groups" are not then mentioned again in the text. What is the relation, and what is the reference for the assertion? Lichfielder (talk) 10:29, 5 October 2012 (UTC)