English
The identity LHom on bounded formulas acts as the identity on each bounded formula.
Русский
Идентичность L-гомоморфизм на ограниченных формулах действует как единичный отображение на каждой ограниченной формуле.
LaTeX
$$$\\text{(LHom.id L).onBoundedFormula} = \\mathrm{id}$$$
Lean4
@[simp]
theorem id_onBoundedFormula : ((LHom.id L).onBoundedFormula : L.BoundedFormula α n → L.BoundedFormula α n) = id :=
by
ext f
induction f with
| falsum => rfl
| equal => rw [onBoundedFormula, LHom.id_onTerm, id, id, id, Term.bdEqual]
| rel => rw [onBoundedFormula, LHom.id_onTerm]; rfl
| imp _ _ ih1 ih2 => rw [onBoundedFormula, ih1, ih2, id, id, id]
| all _ ih3 => rw [onBoundedFormula, ih3, id, id]