Nuprl Lemma : fset-union-closed

[T:Type]. ∀[eq:EqDecider(T)]. ∀[fs:(T ⟶ T) List]. ∀[as,bs:fset(T)].
  ((as ⋃ bs closed under fs)) supposing ((bs closed under fs) and (as closed under fs))


Proof




Definitions occuring in Statement :  fset-closed: (s closed under fs) fset-union: x ⋃ y fset: fset(T) list: List deq: EqDecider(T) uimplies: supposing a uall: [x:A]. B[x] function: x:A ⟶ B[x] universe: Type
Definitions unfolded in proof :  fset-closed: (s closed under fs) uall: [x:A]. B[x] member: t ∈ T uimplies: supposing a all: x:A. B[x] so_lambda: λ2x.t[x] prop: so_apply: x[s] iff: ⇐⇒ Q and: P ∧ Q implies:  Q rev_implies:  Q l_all: (∀x∈L.P[x]) int_seg: {i..j-} guard: {T} lelt: i ≤ j < k decidable: Dec(P) or: P ∨ Q satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] false: False not: ¬A top: Top less_than: a < b squash: T
Lemmas referenced :  member-fset-union deq_wf list_wf fset_wf l_all_wf int_seg_wf int_formula_prop_less_lemma intformless_wf decidable__lt int_formula_prop_wf int_term_value_var_lemma int_term_value_constant_lemma int_formula_prop_le_lemma int_formula_prop_not_lemma int_formula_prop_and_lemma itermVar_wf itermConstant_wf intformle_wf intformnot_wf intformand_wf satisfiable-full-omega-tt decidable__le length_wf int_seg_properties select_wf fset-member_witness fset-union_wf l_member_wf fset-member_wf isect_wf all_wf l_all_iff
Rules used in proof :  sqequalSubstitution sqequalRule sqequalReflexivity sqequalTransitivity computationStep isect_memberFormation introduction cut lemma_by_obid sqequalHypSubstitution isectElimination thin functionEquality hypothesisEquality dependent_functionElimination lambdaEquality hypothesis applyEquality setElimination rename setEquality productElimination independent_functionElimination lambdaFormation because_Cache isect_memberEquality cumulativity independent_isectElimination natural_numberEquality unionElimination dependent_pairFormation int_eqEquality intEquality voidElimination voidEquality independent_pairFormation computeAll imageElimination equalityTransitivity equalitySymmetry universeEquality inlFormation inrFormation

Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[fs:(T  {}\mrightarrow{}  T)  List].  \mforall{}[as,bs:fset(T)].
    ((as  \mcup{}  bs  closed  under  fs))  supposing  ((bs  closed  under  fs)  and  (as  closed  under  fs))



Date html generated: 2016_05_14-PM-03_44_48
Last ObjectModification: 2016_01_14-PM-10_39_59

Theory : finite!sets


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