| rmdup(x0) = [] → x0 = [], rmdup(a + x0) = [] ⊦ a + x0 = [] |
rmdup(a ' + x0) = [] ⊦ x0 = [], rmdup(x0) = []
Used simplifier rules: rm-one: ⊦ rmdup(a ') = a ';%e: ⊦ a ' ≠ []; from specification list%app: ⊦ x + [] = x; from specification list%a: ⊦ (x + y) + z = x + y + z; from specification list%e-01: ⊦ a ' + x ≠ []; from specification list%c: ⊦ a + x = a ' + x; from specification list