\origofThe symbol \origof is used to denote the original of a function or mapping in mathematical contexts. It is often used in discussions involving inverse functions or mappings, where one is interested in the original value or set of values that map to a given result.
Finding the original value that maps to y under the function f.
f(\origof(y)) = yExpressing that x is the original value before applying the function f.
\origof(f(x)) = xRelating the original value of z under function g to another function h.
g(\origof(z)) = h(z)