| ∀ b. count(b, bag1) = (a = b ⊃ 1;0) + count(b, bag0) ⊦ ∀ a0. count(a0, bag1) = count(a0, bag0 ++ a) |
∀ b. count(b, bag1) = (a = b ⊃ 1;0) + count(b, bag0) ⊦ count(a0, bag1) = (a0 = a ⊃ 1;0) + count(a0, bag0)
Used simplifier rules: count-insert: ⊦ count(a, bag ++ b) = (a = b ⊃ 1;0) + count(a, bag);