Nuprl Lemma : double_isect_subtype_rel
∀[T1,T2:Type]. ∀[B:T1 ⟶ T2 ⟶ Type]. ∀[x:T1]. ∀[y:T2].  ((⋂x:T1. ⋂y:T2.  B[x;y]) ⊆r B[x;y])
Proof
Definitions occuring in Statement : 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s1;s2]
, 
isect: ⋂x:A. B[x]
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
so_apply: x[s1;s2]
, 
subtype_rel: A ⊆r B
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
prop: ℙ
Lemmas referenced : 
equal_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalRule, 
lambdaEquality, 
isectElimination, 
hypothesisEquality, 
equalityTransitivity, 
equalitySymmetry, 
hypothesis, 
thin, 
isectEquality, 
cumulativity, 
applyEquality, 
functionExtensionality, 
lambdaFormation, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
independent_functionElimination, 
axiomEquality, 
isect_memberEquality, 
because_Cache, 
functionEquality, 
universeEquality
Latex:
\mforall{}[T1,T2:Type].  \mforall{}[B:T1  {}\mrightarrow{}  T2  {}\mrightarrow{}  Type].  \mforall{}[x:T1].  \mforall{}[y:T2].    ((\mcap{}x:T1.  \mcap{}y:T2.    B[x;y])  \msubseteq{}r  B[x;y])
Date html generated:
2017_04_14-AM-07_14_04
Last ObjectModification:
2017_02_27-PM-02_49_57
Theory : subtype_0
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