| ¬ a0 ∈ y, a ∈ y, ∀ a, y. a ∈ y → #oc(a, filter(x0, y)) = #oc(a, x0) ⊦ a0 = a, #oc(a, filter(a0 ' + x0, y)) = #oc(a, x0) |
a ∈ y, ∀ a, y. a ∈ y → #oc(a, filter(x0, y)) = #oc(a, x0) ⊦ #oc(a, filter(x0, y)) = #oc(a, x0), a0 ∈ y
Used simplifier rules: a: ⊦ (x + y) + z = x + y + z; from specification list%filt-n: ⊦ ¬ a ∈ y → filter(a ' + x, y) = filter(x, y); from specification list-set