Source: cirosantilli/symmetric-bilinear-map
= Symmetric bilinear map
{wiki}
Subcase of <symmetric multilinear map>:
$$
f(x, y) = f(y, x)
$$
Requires the two inputs $x$ and $y$ to be in the same <vector space> of course.
The most important example is the <dot product>, which is also a <positive definite symmetric bilinear form>.