| n ≤ # kar ⊦ ki ∈ keyset(kar, n) ↔ (∃ m. m < n ∧ ki = kar[m]) |
n0 +1 ≤ # kar, ∀ kar, ki. n0 ≤ # kar → (ki ∈ keyset(kar, n0) ↔ (∃ m. m < n0 ∧ ki = kar[m])) ⊦ ki ∈ keyset(kar, n0 +1) ↔ (∃ m. m < n0 +1 ∧ ki = kar[m])
Used simplifier rules: keyset-base: ⊦ keyset(kar, 0) = ∅;%nat freely generated by 0, +1;;% ⊦ ¬ ki ∈ ∅; (s)% ⊦ ¬ m < 0; (s)