How standard is the f \circ (g, h) notation for composition of n-ary functions? I do see it in Wikipedia, but I hadn't come across it myself until looking at Su

How standard is the f \circ (g, h) notation for composition of n-ary functions? I do see it in Wikipedia, but I hadn't come across it myself until looking at Sussman et al. Structure and Interpretation of Classical Mechanics. https://en.wikipedia.org/wiki/Function_composition#Multivariate_functions https://en.wikipedia.org/wiki/Function_composition#Multivari...