Magma has a sophisticated machinery for coercion of elements into structures other than the parent. Non-automatic coercion is usually performed via the ! operator. To obtain the coercion map corresponding to ! in a particular instance the Coercion function can be used.

Coercion(D, C) : Struct, Struct -> Map

Bang(D, C) : Struct, Struct -> Map

Given structures D and C such that elements from D can be coerced into C, return the map m that performs this coercion. Thus the domain of m will be D and the codomain will be C.