law join_prepend
import stelliferous@0.0.2.0/proofs/word_encoding.bend as WordEncodingimport Base
167law join_prepend:
168 for +n: Nat
169 for +m: Nat
170 for +b: Bool
171 for +parts: Split<n,m>
172 {WCon{b,join(n,m,parts)} == join(1n+n,m,prepend(n,m,b,parts)) : Word(1n+Nat.add(n,m))}