| x1 = 3 ' + 2 ' + 2 ', to3 = fail, x0 = x1 ∧ d0 = 2, h0 = head(x0) ⊦ 〈if h0 < d0 then to := fail else if h0 = d0 then { x0 := pop(x0) ; to := some(Leaf) } else let to0 = fail, to1 = fail in { build_rec#(d0 + 1; x0, to0) ; if to0 = fail then to := fail else { build_rec#(d0 + 1; x0, to1) ; if to1 = fail then to := fail else to := some(Node(to0 .t, to1 .t)) } }〉 〈to3 := to, x1 := x0 ; if to3 = fail then to := fail else { to2 := fail ; build_rec#(2; x1, to2) ; if to2 = fail then to := fail else to := some(Node(to3 .t, to2 .t)) }〉 〈to4 := to ; if to4 = fail then to0 := fail else to0 := some(Node(Leaf, to4 .t))〉 〈to1 := to0 ; if x1 ≠ [] then to1 := fail〉 to1 = fail |
x1 = 3 ' + 2 ' + 2 ', to3 = fail, x0 = x1 ∧ d0 = 2, h0 = head(x0) ⊦ 〈if h0 = d0 then { x0 := pop(x0) ; to := some(Leaf) } else let to0 = fail, to1 = fail in { build_rec#(d0 + 1; x0, to0) ; if to0 = fail then to := fail else { build_rec#(d0 + 1; x0, to1) ; if to1 = fail then to := fail else to := some(Node(to0 .t, to1 .t)) } }〉 〈to3 := to, x1 := x0 ; if to3 = fail then to := fail else { to2 := fail ; build_rec#(2; x1, to2) ; if to2 = fail then to := fail else to := some(Node(to3 .t, to2 .t)) }〉 〈to4 := to ; if to4 = fail then to0 := fail else to0 := some(Node(Leaf, to4 .t))〉 〈to1 := to0 ; if x1 ≠ [] then to1 := fail〉 to1 = fail
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ head(d ' + x) = d], [CSIMPSEQ : ⊦ (x + y) + z = x + y + z])]]