Nuprl Lemma : trivial_map

∀[T:Type]. ∀[a:T List]. ∀[f:T ⟶ T].  map(f;a) = a ∈ (T List) supposing ∀x:T. ((x ∈ a) ⇒ ((f x) = x ∈ T))


Proof




Definitions occuring in Statement :  l_member: (x ∈ l),  map: map(f;as),  list: T List,  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  all: ∀x:A. B[x],  implies: P ⇒ Q,  apply: f a,  function: x:A ⟶ B[x],  universe: Type,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  uimplies: b supposing a,  so_lambda: λ2x.t[x],  implies: P ⇒ Q,  prop: ℙ,  so_apply: x[s],  all: ∀x:A. B[x],  top: Top,  squash: ↓T,  guard: {T},  iff: P ⇐⇒ Q,  and: P ∧ Q,  rev_implies: P ⇐ Q,  or: P ∨ Q,  true: True,  subtype_rel: A ⊆r B
Lemmas referenced :  list_induction,  all_wf,  l_member_wf,  equal_wf,  list_wf,  map_wf,  map_nil_lemma,  nil_wf,  map_cons_lemma,  squash_wf,  true_wf,  cons_wf,  cons_member,  iff_weakening_equal
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  thin,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  hypothesisEquality,  sqequalRule,  lambdaEquality,  functionEquality,  cumulativity,  hypothesis,  applyEquality,  functionExtensionality,  independent_functionElimination,  dependent_functionElimination,  isect_memberEquality,  voidElimination,  voidEquality,  lambdaFormation,  rename,  imageElimination,  equalityTransitivity,  equalitySymmetry,  because_Cache,  productElimination,  inrFormation,  natural_numberEquality,  imageMemberEquality,  baseClosed,  independent_isectElimination,  universeEquality,  inlFormation,  axiomEquality

Latex:
\mforall{}[T:Type].  \mforall{}[a:T  List].  \mforall{}[f:T  {}\mrightarrow{}  T].    map(f;a)  =  a  supposing  \mforall{}x:T.  ((x  \mmember{}  a)  {}\mRightarrow{}  ((f  x)  =  x))



Date html generated: 2017_04_14-AM-08_54_22
Last ObjectModification: 2017_02_27-PM-03_38_47

Theory : list_0


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