| ⊦ a ∈ prefixn(n, x) ∧ m ≤ pos(a, x) → m ≤ n |
⊦ prefixn(n, x) = (n ≤ # x ⊃ firstn(n, x);x)
[Concretesimprules((Csimpnamedseq(prefixn,,, ⊦ prefixn(n, x) = (n ≤ # x ⊃ firstn(n, x);x)) Csimpnamedseq(list-del,,len-01, ⊦ ¬ # x < pos(a, x)) Csimpnamedseq(nat-basic2,,succ, ⊦ m +1 = m + 1) Csimpnamedforward(nat-basic1,,trans-1, ⊦ n < n0 ∧ n0 < n1 → n < n1) Csimpnamedforward(nat-basic1,,lf, ⊦ m < n ∧ n < n0 → m +1 < n0) Csimpnamedforward(nat-basic1,,f, ⊦ m < n → n ≠ 0) Csimpnamedforward(nat,,fle, ⊦ m < n ∧ n ≤ n0 → m < n0) Csimpnamedseq(nat,,lels-01, ⊦ ¬ m ≤ n ↔ n < m)))]