Proof 01. 1 ⊢ closure_operator H U, hypo. 02. 2 ⊢ X ⊆ U, hypo. 03. 1 ⊢ set U ∧ map H (power U) (power U), lsubj_conj_elimlll clop_equi 1. 04. 1 ⊢ set U, conj_eliml 3. 05. 1 ⊢ map H (power U) (power U), conj_elimr 3. 06. 1, 2 ⊢ set X, subset 2 4. 07. 1, 2 ⊢ X ∈ power U, power_intro 6 2. 08. 1, 2 ⊢ app H X ∈ power U, map_app_in_cod 5 7. 09. 1, 2 ⊢ app H X ⊆ U, power_elim 8. clop_app_in_cod. ⊢ closure_operator H U → X ⊆ U → app H X ⊆ U, subj_intro_ii 9.
Dependencies
The given proof depends on seven axioms:
comp, efq, eq_refl, eq_subst, ext, lem, subset.