A Complete Axiom System for Isomorphism of Types in Closed Categories

It is shown, that ordinary isomorphisms (associativity and commutativity of tensor, isomorphisms for tensor unit and currying) provide a complete axiom system for the isomorphism of types in Symmetric Monoidal Closed categories. This gives also a decision algorithm. The problem originally arises from computer science, as the isomorphism of types in SMC categories corresponds to the isomorphism of types in linear lambda calculus, and could be used for search in databases.