law take_append

bend-mathlib@0.8.1.0 · list.bend:1108

import Base

1108# Taking past the first part of an append keeps it and takes the rest from the second part.
1109law take_append:
1110  for -a: Quant
1111  for -A: Kind(a)
1112  for xs: List<a, A>
1113  for -ys: List<a, A>
1114  for -n: Nat
1115  {List.take(a, A, List.append(a, A, xs, ys), Nat.add(List.length(a, A, xs), n)) == List.append(a, A, xs, List.take(a, A, ys, n)) : List<a, A>}