Nuprl Lemma : member-intersection
∀[A:Type]. ∀eq:EqDecider(A). ∀L1,L2:A List. ∀x:A.  ((x ∈ l_intersection(eq;L1;L2)) 
⇐⇒ (x ∈ L1) ∧ (x ∈ L2))
Proof
Definitions occuring in Statement : 
l_intersection: l_intersection(eq;L1;L2)
, 
l_member: (x ∈ l)
, 
list: T List
, 
deq: EqDecider(T)
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
l_intersection: l_intersection(eq;L1;L2)
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
assert-deq-member, 
assert_wf, 
deq-member_wf, 
iff_wf, 
and_wf, 
l_member_wf, 
member_filter, 
filter_wf5, 
list_wf, 
deq_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
sqequalRule, 
addLevel, 
sqequalHypSubstitution, 
productElimination, 
thin, 
independent_pairFormation, 
impliesFunctionality, 
hypothesis, 
lemma_by_obid, 
isectElimination, 
because_Cache, 
dependent_functionElimination, 
hypothesisEquality, 
independent_functionElimination, 
andLevelFunctionality, 
lambdaEquality, 
cumulativity, 
setElimination, 
rename, 
setEquality, 
universeEquality
Latex:
\mforall{}[A:Type]
    \mforall{}eq:EqDecider(A).  \mforall{}L1,L2:A  List.  \mforall{}x:A.    ((x  \mmember{}  l\_intersection(eq;L1;L2))  \mLeftarrow{}{}\mRightarrow{}  (x  \mmember{}  L1)  \mwedge{}  (x  \mmember{}  L2))
Date html generated:
2016_05_14-PM-03_32_30
Last ObjectModification:
2015_12_26-PM-06_01_25
Theory : decidable!equality
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