olemus
kompleksarvuliste väärtustega bilineaarne funktsioon f,
mis rahuldab tingimusi:
(i) f(x,x) on mittenegatiivne reaalarv
(ii) kui f(x,x)=0 mingi vektori x korral, siis x on nullvektor
=
a complex-valued bilinear function f satisfying the following conditions:
(i) f (x,x) is a nonnegative real number
(ii) if f (x,x) = 0 for some vector x, then x is a zero vector

ülevaateid
https://en.wikipedia.org/wiki/Definite_quadratic_form

http://www.math.toronto.edu/mein/teaching/LieClifford/cl12.pdf