Nuprl Lemma : combine-list-member

∀[T:Type]
  ∀f:T ⟶ T ⟶ T. ∀L:T List.
    ((∀x,y:T.  ((f[x;y] = x ∈ T) ∨ (f[x;y] = y ∈ T))) ⇒ 0 < ||L|| ⇒ (combine-list(x,y.f[x;y];L) ∈ L))


Proof




Definitions occuring in Statement :  combine-list: combine-list(x,y.f[x; y];L),  l_member: (x ∈ l),  length: ||as||,  list: T List,  less_than: a < b,  uall: ∀[x:A]. B[x],  so_apply: x[s1;s2],  all: ∀x:A. B[x],  implies: P ⇒ Q,  or: P ∨ Q,  function: x:A ⟶ B[x],  natural_number: $n,  universe: Type,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  all: ∀x:A. B[x],  implies: P ⇒ Q,  member: t ∈ T,  or: P ∨ Q,  less_than: a < b,  squash: ↓T,  less_than': less_than'(a;b),  false: False,  and: P ∧ Q,  cons: [a / b],  top: Top,  combine-list: combine-list(x,y.f[x; y];L),  so_lambda: λ2x.t[x],  so_lambda: λ2x y.t[x; y],  so_apply: x[s1;s2],  so_apply: x[s],  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  prop: ℙ,  guard: {T}
Lemmas referenced :  list-cases,  length_of_nil_lemma,  product_subtype_list,  length_of_cons_lemma,  reduce_hd_cons_lemma,  reduce_tl_cons_lemma,  list_induction,  all_wf,  l_member_wf,  list_accum_wf,  cons_wf,  list_wf,  list_accum_nil_lemma,  list_accum_cons_lemma,  cons_member,  equal_wf,  less_than_wf,  length_wf,  or_wf,  member_wf,  member_singleton
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  lambdaFormation,  cut,  hypothesisEquality,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesis,  dependent_functionElimination,  unionElimination,  sqequalRule,  imageElimination,  productElimination,  voidElimination,  promote_hyp,  hypothesis_subsumption,  isect_memberEquality,  voidEquality,  lambdaEquality,  cumulativity,  applyEquality,  functionExtensionality,  independent_functionElimination,  rename,  because_Cache,  hyp_replacement,  equalitySymmetry,  Error :applyLambdaEquality,  inrFormation,  natural_numberEquality,  functionEquality,  universeEquality,  addLevel,  allFunctionality,  inlFormation,  orFunctionality

Latex:
\mforall{}[T:Type]
    \mforall{}f:T  {}\mrightarrow{}  T  {}\mrightarrow{}  T.  \mforall{}L:T  List.
        ((\mforall{}x,y:T.    ((f[x;y]  =  x)  \mvee{}  (f[x;y]  =  y)))  {}\mRightarrow{}  0  <  ||L||  {}\mRightarrow{}  (combine-list(x,y.f[x;y];L)  \mmember{}  L))



Date html generated: 2016_10_21-AM-09_49_46
Last ObjectModification: 2016_07_12-AM-05_09_20

Theory : list_0


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