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: List less_than: a < b uall: [x:A]. B[x] so_apply: x[s1;s2] all: x:A. B[x] implies:  Q or: P ∨ Q function: x:A ⟶ B[x] natural_number: $n universe: Type equal: t ∈ T
Definitions unfolded in proof :  uall: [x:A]. B[x] all: x:A. B[x] implies:  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: λ2y.t[x; y] so_apply: x[s1;s2] so_apply: x[s] iff: ⇐⇒ Q rev_implies:  Q prop: 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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