bilinear

Linear (preserving linear combinations) in each variable.

The function f(x,y)#61;xy is bilinear, because f(ax#43;bu,y)#61;af(x,y)#43;bf(u,y) and f(x,ay#43;bv)#61;af(x,y)#43;bf(x,v) for all values.

Of or pertaining to a Möbius transformation (type of conformal map representable as the ratio of two linear functions).

bilinear isotropic hardening

A bilinear function.