| (a0[P0] * R0)[rs, f, g], ∃ rs0, rs1. rs0 ∪ rs1 = rs ∧ rs0 ∩ rs1 = ∅ ∧ a[P][rs0, f, g] ∧ R[rs1, f, g] ⊦ a0 = a, (a[P] * a0[P0] * true)[rs, f, g] |
rs1 ∩ rs0 = ∅, a[P][rs1, f, g], R[rs0, f, g], (a0[P0] * R0)[rs1 ∪ rs0, f, g] ⊦ a0 = a, (a[P] * a0[P0] * true)[rs1 ∪ rs0, f, g]