[Imprint][Data Privacy Statement][E-Mail]



View long theorem info. View the proof. Back to main index. View the specification. View theorem base summary, View theorem base listing, the used properties by spec, the dependency list, the symbol table,

Proof step 8 from proof lastN-in-01 (previous step)

n0 < # x, a ∈ lastn(n0, x.butlast), ∀ a, x. a ∈ lastn(n0, x) ∧ n0 ≤ # x → a ∈ x ⊦ a = x.last, x = [], a ∈ x

Heuristic quantifier closing applied rule all left

And closed the goal!

Rule argument

pos: left 3 terms: a, x.butlast

Additional information

Used simplifier rules: ⊦ x ≠ [] → # x.butlast = # x - 1; (s)% ⊦ m ≤ n ↔ ¬ n < m; (ss)% ⊦ m < 1 ↔ m = 0; (s)% ⊦ # x = 0 ↔ x = []; (s)%n0 ≤ n ⊦ m ≤ n - n0 ↔ m + n0 ≤ n; (s)% ⊦ m + 1 ≤ n ↔ m < n; (s)%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic%c: ⊦ m + n = n + m; from specification nat-basic%bin-01: x ≠ [] ⊦ a ∈ x.butlast → a ∈ x; (forward) from specification list-last Used terms: a, x.butlast