Nuprl Lemma : sub-presheaf-set_functionality
∀[C:SmallCategory]. ∀[X:ps_context{j:l}(C)]. ∀[P,Q:I:cat-ob(C) ⟶ X(I) ⟶ ℙ].
  X | I,rho.P[I;rho] ≡ X | I,rho.Q[I;rho] 
  supposing (∀I:cat-ob(C). ∀rho:X(I).  (P[I;rho] 
⇐⇒ Q[I;rho])) ∧ psc-predicate(C; X; I,rho.P[I;rho])
Proof
Definitions occuring in Statement : 
sub-presheaf-set: X | I,rho.P[I; rho]
, 
psc-predicate: psc-predicate(C; X; I,rho.P[I; rho])
, 
I_set: A(I)
, 
ext-eq-psc: X ≡ Y
, 
ps_context: __⊢
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s1;s2]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
function: x:A ⟶ B[x]
, 
cat-ob: cat-ob(C)
, 
small-category: SmallCategory
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
and: P ∧ Q
, 
ext-eq-psc: X ≡ Y
, 
ext-equal-presheaves: ext-equal-presheaves(C;F;G)
, 
sub-presheaf-set: X | I,rho.P[I; rho]
, 
presheaf-subset: F|I,rho.P[I; rho]
, 
mk-presheaf: mk-presheaf, 
all: ∀x:A. B[x]
, 
so_lambda: so_lambda3, 
so_apply: x[s1;s2;s3]
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
subtype_rel: A ⊆r B
, 
ps_context: __⊢
, 
so_apply: x[s1;s2]
, 
prop: ℙ
, 
I_set: A(I)
, 
ext-eq: A ≡ B
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
rev_implies: P 
⇐ Q
, 
so_lambda: λ2x y.t[x; y]
, 
guard: {T}
, 
psc-predicate: psc-predicate(C; X; I,rho.P[I; rho])
, 
stable-element-predicate: stable-element-predicate(C;F;I,rho.P[I; rho])
Lemmas referenced : 
ob_mk_functor_lemma, 
arrow_mk_functor_lemma, 
functor-arrow_wf, 
op-cat_wf, 
type-cat_wf, 
subtype_rel-equal, 
cat-ob_wf, 
cat_ob_op_lemma, 
cat-arrow_wf, 
op-cat-arrow, 
functor-ob_wf, 
I_set_wf, 
psc-predicate_wf, 
small-category-cumulativity-2, 
ps_context_cumulativity2, 
ps_context_wf, 
small-category_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
sqequalHypSubstitution, 
productElimination, 
thin, 
independent_pairFormation, 
sqequalRule, 
extract_by_obid, 
dependent_functionElimination, 
Error :memTop, 
hypothesis, 
lambdaFormation_alt, 
because_Cache, 
lambdaEquality_alt, 
setElimination, 
rename, 
dependent_set_memberEquality_alt, 
applyEquality, 
instantiate, 
isectElimination, 
hypothesisEquality, 
independent_isectElimination, 
universeIsType, 
setIsType, 
independent_pairEquality, 
axiomEquality, 
functionIsTypeImplies, 
inhabitedIsType, 
productIsType, 
functionIsType, 
cumulativity, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
universeEquality, 
independent_functionElimination
Latex:
\mforall{}[C:SmallCategory].  \mforall{}[X:ps\_context\{j:l\}(C)].  \mforall{}[P,Q:I:cat-ob(C)  {}\mrightarrow{}  X(I)  {}\mrightarrow{}  \mBbbP{}].
    X  |  I,rho.P[I;rho]  \mequiv{}  X  |  I,rho.Q[I;rho] 
    supposing  (\mforall{}I:cat-ob(C).  \mforall{}rho:X(I).    (P[I;rho]  \mLeftarrow{}{}\mRightarrow{}  Q[I;rho]))
    \mwedge{}  psc-predicate(C;  X;  I,rho.P[I;rho])
Date html generated:
2020_05_20-PM-01_23_31
Last ObjectModification:
2020_04_01-AM-10_45_19
Theory : presheaf!models!of!type!theory
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