Nuprl Lemma : bag-member-iff-hd

∀[T:Type]. ∀[bs:bag(T)]. ∀[x:T].  uiff(x ↓∈ bs;↓∃L:T List. (bs = [x / L] ∈ bag(T)))


Proof




Definitions occuring in Statement :  bag-member: x ↓∈ bs,  bag: bag(T),  cons: [a / b],  list: T List,  uiff: uiff(P;Q),  uall: ∀[x:A]. B[x],  exists: ∃x:A. B[x],  squash: ↓T,  universe: Type,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  uiff: uiff(P;Q),  and: P ∧ Q,  uimplies: b supposing a,  squash: ↓T,  prop: ℙ,  bag-member: x ↓∈ bs,  so_lambda: λ2x.t[x],  subtype_rel: A ⊆r B,  so_apply: x[s],  exists: ∃x:A. B[x],  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  implies: P ⇒ Q,  true: True,  bag: bag(T),  so_lambda: λ2x y.t[x; y],  so_apply: x[s1;s2],  append: as @ bs,  so_lambda: so_lambda(x,y,z.t[x; y; z]),  top: Top,  so_apply: x[s1;s2;s3],  rev_implies: P ⇐ Q,  cand: A c∧ B,  or: P ∨ Q
Lemmas referenced :  bag-member_wf,  squash_wf,  exists_wf,  list_wf,  equal_wf,  bag_wf,  cons_wf,  list-subtype-bag,  l_member_decomp,  append_wf,  true_wf,  quotient-member-eq,  permutation_wf,  permutation-equiv,  nil_wf,  list_ind_cons_lemma,  list_ind_nil_lemma,  permutation_functionality_wrt_permutation,  cons_functionality_wrt_permutation,  permutation-rotate,  permutation_weakening,  cons_member,  l_member_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  independent_pairFormation,  hypothesis,  sqequalHypSubstitution,  imageElimination,  sqequalRule,  imageMemberEquality,  hypothesisEquality,  thin,  baseClosed,  extract_by_obid,  isectElimination,  cumulativity,  lambdaEquality,  applyEquality,  because_Cache,  independent_isectElimination,  productElimination,  independent_pairEquality,  isect_memberEquality,  equalityTransitivity,  equalitySymmetry,  universeEquality,  dependent_functionElimination,  independent_functionElimination,  dependent_pairFormation,  hyp_replacement,  natural_numberEquality,  applyLambdaEquality,  voidElimination,  voidEquality,  inlFormation,  productEquality

Latex:
\mforall{}[T:Type].  \mforall{}[bs:bag(T)].  \mforall{}[x:T].    uiff(x  \mdownarrow{}\mmember{}  bs;\mdownarrow{}\mexists{}L:T  List.  (bs  =  [x  /  L]))



Date html generated: 2017_10_01-AM-08_53_49
Last ObjectModification: 2017_07_26-PM-04_35_30

Theory : bags


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