| depths(t, i + 1) + depths(t0, i + 1) ≠ [], i = head(depths(t, i + 1) + depths(t0, i + 1)) ∧ x = pop(depths(t, i + 1) + depths(t0, i + 1)) + y, i ∈ depths(t, i + 1) ⊦ |
i = head(depths(t, i + 1)), i ∈ depths(t, i + 1) ⊦ depths(t, i + 1) + depths(t0, i + 1) = []
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ (x + y) + z = x + y + z], [CSIMPSEQ : ⊦ d ∈ x → head(x + y) = head(x)], [CSIMPSEQ : ⊦ i + j = j + i])]]