| ⊦ count(a, bag1) = 0, (∀ a0. count(a0, bag0) ≤ count(a0, bag1) - (a0 = a ⊃ 1;0)) ↔ (∀ a0. count(a0, bag0 ++ a) ≤ count(a0, bag1)) |
∀ a0. count(a0, bag0) ≤ count(a0, bag1) - (a0 = a ⊃ 1;0) ⊦ ∀ a0. count(a0, bag0 ++ a) ≤ count(a0, bag1), count(a, bag1) = 0
∀ a0. count(a0, bag0 ++ a) ≤ count(a0, bag1) ⊦ ∀ a0. count(a0, bag0) ≤ count(a0, bag1) - (a0 = a ⊃ 1;0), count(a, bag1) = 0