| ∃ H0, H1. H0 ⊥ H1 ∧ H ++ r = H0 ∪ H1 ∧ ((r => o))(H0) ∧ P(H1) ⊦ r = null, P(H), r ∈ H |
H ++ r = (∅ ++ r)[r, o] ∪ H0, P(H0) ⊦ r = null, P(H), r ∈ H, r ∈ H0
Used simplifier rules: maplet: ⊦ ((r => o))(H) ↔ H = (∅ ++ r)[r, o] ∧ r ≠ null;%r ≠ null ⊦ (∅ ++ r)[r, o] ⊥ H ↔ ¬ r ∈ H; (s)