Nuprl Lemma : isect2_subtype_rel3
∀[A,B,C:Type].  A ⋂ B ⊆r C supposing (A ⊆r C) ∨ (B ⊆r C)
Proof
Definitions occuring in Statement : 
isect2: T1 ⋂ T2
, 
uimplies: b supposing a
, 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
or: P ∨ Q
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
or: P ∨ Q
, 
subtype_rel: A ⊆r B
, 
prop: ℙ
Lemmas referenced : 
or_wf, 
subtype_rel_wf, 
subtype_rel_transitivity, 
isect2_wf, 
isect2_subtype_rel, 
isect2_subtype_rel2
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalHypSubstitution, 
unionElimination, 
thin, 
sqequalRule, 
axiomEquality, 
hypothesis, 
lemma_by_obid, 
isectElimination, 
hypothesisEquality, 
isect_memberEquality, 
because_Cache, 
equalityTransitivity, 
equalitySymmetry, 
universeEquality, 
independent_isectElimination
Latex:
\mforall{}[A,B,C:Type].    A  \mcap{}  B  \msubseteq{}r  C  supposing  (A  \msubseteq{}r  C)  \mvee{}  (B  \msubseteq{}r  C)
Date html generated:
2016_05_13-PM-03_58_10
Last ObjectModification:
2015_12_26-AM-10_51_07
Theory : bool_1
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