Proof step 3 from proof k-intersect-rec2 (previous step)
¬ a ∈ s ∨ ¬ a ∈ s0 ⊦ a0 ∈ s ∧ a0 ∈ s0 ↔ a0 ∈ s -- a ∧ a0 ∈ s0 -- a
Heuristic weak cut applied rule cut formula
And closed the goal!
Rule argument
fma: a ∈ s0
Additional information
Used simplifier rules:
Delete: ⊦ a ∈ s -- b ↔ a ≠ b ∧ a ∈ s;%Delete: ⊦ a ∈ s -- b ↔ a ≠ b ∧ a ∈ s;%del-in: ⊦ ¬ a ∈ s → s -- a = s;
Used formulas: a ∈ s0