Nuprl Lemma : decide-isint-if-has-value

∀t,a,b:Base.  ((t)↓ ⇒ ((if t is an integer then a else b ~ a) ∨ (if t is an integer then a else b ~ b)))


Proof




Definitions occuring in Statement :  has-value: (a)↓,  isint: isint def,  all: ∀x:A. B[x],  implies: P ⇒ Q,  or: P ∨ Q,  base: Base,  sqequal: s ~ t
Definitions unfolded in proof :  all: ∀x:A. B[x],  implies: P ⇒ Q,  has-value: (a)↓,  member: t ∈ T,  uall: ∀[x:A]. B[x],  or: P ∨ Q,  top: Top,  guard: {T},  prop: ℙ
Lemmas referenced :  base_wf,  top_wf,  is-exception_wf,  has-value_wf_base
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  isintCases,  divergentSqle,  hypothesis,  cut,  lemma_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  baseClosed,  hypothesisEquality,  sqequalRule,  isintReduceTrue,  equalityTransitivity,  equalitySymmetry,  because_Cache,  inlFormation,  sqequalIntensionalEquality,  isect_memberFormation,  introduction,  sqequalAxiom,  isect_memberEquality,  voidElimination,  voidEquality,  inrFormation

Latex:
\mforall{}t,a,b:Base.
    ((t)\mdownarrow{}  {}\mRightarrow{}  ((if  t  is  an  integer  then  a  else  b  \msim{}  a)  \mvee{}  (if  t  is  an  integer  then  a  else  b  \msim{}  b)))



Date html generated: 2016_05_13-PM-03_22_30
Last ObjectModification: 2016_01_14-PM-06_46_45

Theory : call!by!value_1


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