⊦ a[P](mk(rs, f, g)) ↔ P(mk(rs, f)) ∧ (∀ r. r ∈ rs → g(r) = a)
(_∃ oP)(mk(rs, f)), ∀ r. r ∈ rs → g(r) = a ⊦ ∃ o. a[oP(o)](mk(rs, f, g))
Used terms: g, f, rs, _∃ oP, a