Nuprl Lemma : context-subset_functionality

∀[Gamma:j⊢]. ∀[a,b:{Gamma ⊢ _:𝔽}].  (Gamma ⊢ (a ⇐⇒ b) ⇒ {Gamma, a ⊢ _} ≡ {Gamma, b ⊢ _})


Proof




Definitions occuring in Statement :  face-term-iff: Gamma ⊢ (phi ⇐⇒ psi),  context-subset: Gamma, phi,  face-type: 𝔽,  cubical-term: {X ⊢ _:A},  cubical-type: {X ⊢ _},  cubical_set: CubicalSet,  ext-eq: A ≡ B,  uall: ∀[x:A]. B[x],  implies: P ⇒ Q
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  implies: P ⇒ Q,  face-term-iff: Gamma ⊢ (phi ⇐⇒ psi),  and: P ∧ Q,  ext-eq: A ≡ B,  uimplies: b supposing a,  face-term-implies: Gamma ⊢ (phi ⇒ psi),  prop: ℙ,  subtype_rel: A ⊆r B
Lemmas referenced :  context-subset-subtype,  face-term-iff_wf,  cubical-term_wf,  face-type_wf,  cubical_set_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation_alt,  introduction,  cut,  lambdaFormation_alt,  sqequalHypSubstitution,  productElimination,  thin,  independent_pairFormation,  extract_by_obid,  isectElimination,  hypothesisEquality,  independent_isectElimination,  hypothesis,  because_Cache,  universeIsType,  instantiate,  sqequalRule,  lambdaEquality_alt,  dependent_functionElimination,  independent_pairEquality,  axiomEquality,  functionIsTypeImplies,  inhabitedIsType,  isect_memberEquality_alt,  isectIsTypeImplies

Latex:
\mforall{}[Gamma:j\mvdash{}].  \mforall{}[a,b:\{Gamma  \mvdash{}  \_:\mBbbF{}\}].    (Gamma  \mvdash{}  (a  \mLeftarrow{}{}\mRightarrow{}  b)  {}\mRightarrow{}  \{Gamma,  a  \mvdash{}  \_\}  \mequiv{}  \{Gamma,  b  \mvdash{}  \_\})



Date html generated: 2020_05_20-PM-02_51_36
Last ObjectModification: 2020_04_06-AM-10_32_20

Theory : cubical!type!theory


Home Index