Nuprl Lemma : compact-product

∀[T:Type]. ∀[S:T ⟶ Type].  (compact-type(T) ⇒ (∀t:T. compact-type(S[t])) ⇒ compact-type(t:T × S[t]))


Proof




Definitions occuring in Statement :  compact-type: compact-type(T),  uall: ∀[x:A]. B[x],  so_apply: x[s],  all: ∀x:A. B[x],  implies: P ⇒ Q,  function: x:A ⟶ B[x],  product: x:A × B[x],  universe: Type
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  implies: P ⇒ Q,  compact-type: compact-type(T),  all: ∀x:A. B[x],  member: t ∈ T,  so_apply: x[s],  prop: ℙ,  so_lambda: λ2x.t[x],  exists: ∃x:A. B[x],  subtype_rel: A ⊆r B,  or: P ∨ Q,  isr: isr(x),  not: ¬A,  false: False,  guard: {T},  squash: ↓T,  true: True,  uimplies: b supposing a,  iff: P ⇐⇒ Q,  and: P ∧ Q,  rev_implies: P ⇐ Q
Lemmas referenced :  bool_wf,  all_wf,  compact-type_wf,  isr_wf,  exists_wf,  equal-wf-T-base,  or_wf,  equal-wf-base,  btrue_neq_bfalse,  equal_wf,  squash_wf,  true_wf,  iff_weakening_equal
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  lambdaFormation,  sqequalHypSubstitution,  sqequalRule,  functionEquality,  productEquality,  cumulativity,  hypothesisEquality,  applyEquality,  functionExtensionality,  cut,  introduction,  extract_by_obid,  hypothesis,  isectElimination,  thin,  lambdaEquality,  universeEquality,  rename,  dependent_functionElimination,  because_Cache,  unionElimination,  productElimination,  inlFormation,  dependent_pairEquality,  baseClosed,  independent_functionElimination,  voidElimination,  equalityTransitivity,  equalitySymmetry,  dependent_pairFormation,  inrFormation,  imageElimination,  equalityUniverse,  levelHypothesis,  natural_numberEquality,  imageMemberEquality,  independent_isectElimination

Latex:
\mforall{}[T:Type].  \mforall{}[S:T  {}\mrightarrow{}  Type].
    (compact-type(T)  {}\mRightarrow{}  (\mforall{}t:T.  compact-type(S[t]))  {}\mRightarrow{}  compact-type(t:T  \mtimes{}  S[t]))



Date html generated: 2017_10_01-AM-08_28_57
Last ObjectModification: 2017_07_26-PM-04_23_44

Theory : basic


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