Nuprl Lemma : sqequal-ff-to-assert

∀[t:𝔹]. uiff(t ~ ff;¬↑t)


Proof




Definitions occuring in Statement :  assert: ↑b,  bfalse: ff,  bool: 𝔹,  uiff: uiff(P;Q),  uall: ∀[x:A]. B[x],  not: ¬A,  sqequal: s ~ t
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  uiff: uiff(P;Q),  and: P ∧ Q,  uimplies: b supposing a,  not: ¬A,  implies: P ⇒ Q,  false: False,  assert: ↑b,  ifthenelse: if b then t else f fi ,  bfalse: ff,  prop: ℙ,  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  sq_type: SQType(T),  all: ∀x:A. B[x],  guard: {T}
Lemmas referenced :  false_wf,  assert_wf,  bool_sq,  subtype_base_sq,  bool_subtype_base,  iff_imp_equal_bool,  bfalse_wf,  not_wf,  bool_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  independent_pairFormation,  lambdaFormation,  thin,  hypothesis,  sqequalRule,  sqequalHypSubstitution,  voidElimination,  lemma_by_obid,  independent_functionElimination,  isectElimination,  hypothesisEquality,  lambdaEquality,  dependent_functionElimination,  because_Cache,  sqequalIntensionalEquality,  instantiate,  independent_isectElimination,  equalityTransitivity,  equalitySymmetry,  sqequalAxiom,  productElimination,  independent_pairEquality,  isect_memberEquality

Latex:
\mforall{}[t:\mBbbB{}].  uiff(t  \msim{}  ff;\mneg{}\muparrow{}t)



Date html generated: 2016_05_15-PM-03_14_32
Last ObjectModification: 2015_12_27-PM-01_02_16

Theory : general


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