Nuprl Lemma : bag-null-bag-union

[T:Type]. ∀[bbs:bag(bag(T))].  ↑bag-null(bag-union(bbs)) supposing ∀bs:bag(T). (bs ↓∈ bbs  (↑bag-null(bs)))


Proof




Definitions occuring in Statement :  bag-member: x ↓∈ bs bag-union: bag-union(bbs) bag-null: bag-null(bs) bag: bag(T) assert: b uimplies: supposing a uall: [x:A]. B[x] all: x:A. B[x] implies:  Q universe: Type
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T uimplies: supposing a squash: T so_lambda: λ2x.t[x] implies:  Q prop: all: x:A. B[x] so_apply: x[s] sq_stable: SqStable(P) exists: x:A. B[x] subtype_rel: A ⊆B empty-bag: {} bag-null: bag-null(bs) null: null(as) bag-union: bag-union(bbs) concat: concat(ll) reduce: reduce(f;k;as) list_ind: list_ind nil: [] it: btrue: tt assert: b ifthenelse: if then else fi  true: True cons-bag: x.b top: Top guard: {T} uiff: uiff(P;Q) and: P ∧ Q rev_uimplies: rev_uimplies(P;Q) cand: c∧ B sq_or: a ↓∨ b or: P ∨ Q iff: ⇐⇒ Q rev_implies:  Q
Lemmas referenced :  bag_to_squash_list bag_wf sq_stable__all all_wf bag-member_wf assert_wf bag-null_wf bag-union_wf sq_stable_from_decidable decidable__assert assert_witness squash_wf list_induction list-subtype-bag subtype_rel_self list_wf empty-bag_wf bag_union_cons_lemma assert_functionality_wrt_uiff bag-append_wf band_wf bag-null-append cons-bag_wf equal-wf-T-base assert-bag-null bag-member-cons iff_transitivity iff_weakening_uiff assert_of_band equal_wf
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation introduction cut thin extract_by_obid sqequalHypSubstitution isectElimination cumulativity hypothesisEquality hypothesis imageElimination sqequalRule lambdaEquality functionEquality dependent_functionElimination independent_functionElimination lambdaFormation because_Cache productElimination promote_hyp rename applyEquality independent_isectElimination natural_numberEquality isect_memberEquality voidElimination voidEquality hyp_replacement equalitySymmetry Error :applyLambdaEquality,  imageMemberEquality baseClosed equalityTransitivity universeEquality productEquality independent_pairFormation inlFormation comment inrFormation

Latex:
\mforall{}[T:Type].  \mforall{}[bbs:bag(bag(T))].
    \muparrow{}bag-null(bag-union(bbs))  supposing  \mforall{}bs:bag(T).  (bs  \mdownarrow{}\mmember{}  bbs  {}\mRightarrow{}  (\muparrow{}bag-null(bs)))



Date html generated: 2016_10_25-AM-10_28_50
Last ObjectModification: 2016_07_12-AM-06_45_09

Theory : bags


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