Nuprl Lemma : cubical-type-restriction-and
∀[X:j⊢]. ∀[T:{X ⊢ _}]. ∀[psi,phi:I:fset(ℕ) ⟶ alpha:X(I) ⟶ T(alpha) ⟶ ℙ].
  (cubical-type-restriction(X;T;I,a,t.psi[I;a;t])
  
⇒ cubical-type-restriction(X;T;I,a,t.phi[I;a;t])
  
⇒ cubical-type-restriction(X;T;I,a,t.psi[I;a;t] ∧ phi[I;a;t]))
Proof
Definitions occuring in Statement : 
cubical-type-restriction: cubical-type-restriction, 
cubical-type-at: A(a)
, 
cubical-type: {X ⊢ _}
, 
I_cube: A(I)
, 
cubical_set: CubicalSet
, 
fset: fset(T)
, 
nat: ℕ
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s1;s2;s3]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
function: x:A ⟶ B[x]
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
cubical-type-restriction: cubical-type-restriction, 
all: ∀x:A. B[x]
, 
and: P ∧ Q
, 
cand: A c∧ B
, 
member: t ∈ T
, 
so_apply: x[s1;s2;s3]
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
so_lambda: so_lambda3, 
guard: {T}
Lemmas referenced : 
istype-cubical-type-at, 
I_cube_wf, 
names-hom_wf, 
cubical-type-restriction_wf, 
cubical_set_cumulativity-i-j, 
cubical-type-cumulativity2, 
fset_wf, 
nat_wf, 
cubical-type_wf, 
cubical_set_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
lambdaFormation_alt, 
sqequalHypSubstitution, 
productElimination, 
thin, 
cut, 
independent_pairFormation, 
hypothesis, 
sqequalRule, 
productIsType, 
universeIsType, 
applyEquality, 
hypothesisEquality, 
introduction, 
extract_by_obid, 
isectElimination, 
because_Cache, 
instantiate, 
lambdaEquality_alt, 
cumulativity, 
inhabitedIsType, 
functionIsType, 
universeEquality, 
dependent_functionElimination, 
independent_functionElimination
Latex:
\mforall{}[X:j\mvdash{}].  \mforall{}[T:\{X  \mvdash{}  \_\}].  \mforall{}[psi,phi:I:fset(\mBbbN{})  {}\mrightarrow{}  alpha:X(I)  {}\mrightarrow{}  T(alpha)  {}\mrightarrow{}  \mBbbP{}].
    (cubical-type-restriction(X;T;I,a,t.psi[I;a;t])
    {}\mRightarrow{}  cubical-type-restriction(X;T;I,a,t.phi[I;a;t])
    {}\mRightarrow{}  cubical-type-restriction(X;T;I,a,t.psi[I;a;t]  \mwedge{}  phi[I;a;t]))
Date html generated:
2020_05_20-PM-03_13_11
Last ObjectModification:
2020_04_06-PM-05_17_17
Theory : cubical!type!theory
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