Nuprl Lemma : not-quotient-true

∀[P:ℙ]. (¬⇃(P) ⇐⇒ ¬P)


Proof




Definitions occuring in Statement :  quotient: x,y:A//B[x; y],  uall: ∀[x:A]. B[x],  prop: ℙ,  iff: P ⇐⇒ Q,  not: ¬A,  true: True
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  iff: P ⇐⇒ Q,  and: P ∧ Q,  implies: P ⇒ Q,  not: ¬A,  false: False,  prop: ℙ,  so_lambda: λ2x y.t[x; y],  so_apply: x[s1;s2],  uimplies: b supposing a,  rev_implies: P ⇐ Q,  quotient: x,y:A//B[x; y],  cand: A c∧ B
Lemmas referenced :  trivial-quotient-true,  istype-universe,  not_wf,  quotient_wf,  true_wf,  equiv_rel_true,  false_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  Error :isect_memberFormation_alt,  introduction,  cut,  independent_pairFormation,  Error :lambdaFormation_alt,  thin,  sqequalHypSubstitution,  independent_functionElimination,  extract_by_obid,  isectElimination,  hypothesisEquality,  hypothesis,  voidElimination,  Error :universeIsType,  cumulativity,  sqequalRule,  Error :lambdaEquality_alt,  Error :inhabitedIsType,  independent_isectElimination,  because_Cache,  productElimination,  independent_pairEquality,  dependent_functionElimination,  Error :functionIsTypeImplies,  universeEquality,  pointwiseFunctionality,  pertypeElimination,  Error :productIsType,  Error :equalityIsType4,  equalityTransitivity,  equalitySymmetry

Latex:
\mforall{}[P:\mBbbP{}].  (\mneg{}\00D9(P)  \mLeftarrow{}{}\mRightarrow{}  \mneg{}P)



Date html generated: 2019_06_20-PM-00_32_37
Last ObjectModification: 2018_10_06-PM-04_17_45

Theory : quot_1


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