Substitution Without Copy and Paste

Defining substitution for a language with binders like the simply typed -calculus requires repetition, defining substitution and renaming separately.To verify the categorical properties of this calculus, we must repeat the same argument many times.We present a lightweight method that avoids repetition and that gives rise to a simply typed category with families (CwF) isomorphic to the initial simply typed CwF.Our paper is a literate Agda script.