| p ∈ ps, ∀ ps0, str. # ps0 < # ps → true → #(str + ps0) = # ps0 ⊦ # ps = 0, #(str + ps) = # ps |
⊦ p ∈ ps ↔ (∃ ps0. ps = ps0 ++ p ∧ ¬ p ∈ ps0)
∃ ps0. ps = ps0 ++ p ∧ ¬ p ∈ ps0, ∀ ps0, str. # ps0 < # ps → true → #(str + ps0) = # ps0 ⊦ #(str + ps) = # ps, # ps = 0
Used terms: ps, p