| (∅)[m] = mkblock(x, lax, m2), st[m] = mkblock(x0, lax0, m3), m3 = 0, inv(st), m ∈ st, @(m, m0, m1) ∈ as, @(m, m0, m1) ∈ st, ∀ n. n ∈ st → st[n].ref-size = (as | n).size ⊦ # as = 0, as = ∅ |
st[m] = mkblock(x0, lax0, 0), (∅)[m] = mkblock(x, lax, m2), inv(st), @(m, m0, m1) ∈ st, @(m, m0, m1) ∈ as, m ∈ st, ∀ n. n ∈ st → st[n].ref-size = (as | n).size ⊦ # as = 0, as = ∅