Nuprl Lemma : is-list-if-has-value-decomp

∀t:ListLike
  ((t)↓
  ⇒ (((↑isaxiom(t)) ∧ (t = Ax ∈ Unit)) ∨ ((↑ispair(t)) ∧ (∃a:Top. ∃b:ListLike. (t = <a, b> ∈ (Top × ListLike))))))


Proof




Definitions occuring in Statement :  is-list-if-has-value: ListLike,  has-value: (a)↓,  assert: ↑b,  bfalse: ff,  btrue: tt,  top: Top,  ispair: if z is a pair then a otherwise b,  isaxiom: if z = Ax then a otherwise b,  all: ∀x:A. B[x],  exists: ∃x:A. B[x],  implies: P ⇒ Q,  or: P ∨ Q,  and: P ∧ Q,  unit: Unit,  pair: <a, b>,  product: x:A × B[x],  equal: s = t ∈ T,  axiom: Ax
Definitions unfolded in proof :  all: ∀x:A. B[x],  implies: P ⇒ Q,  member: t ∈ T,  uall: ∀[x:A]. B[x],  prop: ℙ,  b-union: A ⋃ B,  tunion: ⋃x:A.B[x],  bool: 𝔹,  unit: Unit,  ifthenelse: if b then t else f fi ,  pi2: snd(t),  or: P ∨ Q,  assert: ↑b,  btrue: tt,  and: P ∧ Q,  true: True,  exists: ∃x:A. B[x],  bfalse: ff,  false: False,  subtype_rel: A ⊆r B,  so_apply: x[s],  so_lambda: λ2x.t[x],  uimplies: b supposing a,  ext-eq: A ≡ B
Lemmas referenced :  is-list-if-has-value-hv-prp,  is-list-if-has-value_wf,  istype-assert,  istype-top,  istype-void,  product-value-type,  equal-value-type,  bunion-value-type,  top_wf,  unit_wf2,  b-union_wf,  termination,  is-list-if-has-value-ext,  bfalse_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation_alt,  universeIsType,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  hypothesis,  inhabitedIsType,  imageElimination,  productElimination,  unionElimination,  equalityElimination,  sqequalRule,  inlEquality_alt,  closedConclusion,  independent_pairEquality,  axiomEquality,  natural_numberEquality,  productIsType,  equalityIsType2,  because_Cache,  baseClosed,  inrEquality_alt,  dependent_pairEquality_alt,  equalityIsType1,  voidElimination,  equalityTransitivity,  equalitySymmetry,  dependent_functionElimination,  independent_functionElimination,  applyEquality,  lambdaEquality_alt,  intEquality,  independent_isectElimination,  productEquality

Latex:
\mforall{}t:ListLike
    ((t)\mdownarrow{}  {}\mRightarrow{}  (((\muparrow{}isaxiom(t))  \mwedge{}  (t  =  Ax))  \mvee{}  ((\muparrow{}ispair(t))  \mwedge{}  (\mexists{}a:Top.  \mexists{}b:ListLike.  (t  =  <a,  b>)))))



Date html generated: 2019_10_16-AM-11_38_04
Last ObjectModification: 2018_10_31-PM-02_27_33

Theory : eval!all


Home Index