Nuprl Lemma : fset-absorption1
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[a,b:fset(T)].  (a ⋃ a ⋂ b = a ∈ fset(T))
Proof
Definitions occuring in Statement : 
fset-intersection: a ⋂ b
, 
fset-union: x ⋃ y
, 
fset: fset(T)
, 
deq: EqDecider(T)
, 
uall: ∀[x:A]. B[x]
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
or: P ∨ Q
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
fset-extensionality, 
fset-union_wf, 
fset-intersection_wf, 
fset-member_witness, 
or_wf, 
fset-member_wf, 
and_wf, 
member-fset-union, 
member-fset-intersection, 
uiff_wf, 
fset_wf, 
deq_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
productElimination, 
independent_isectElimination, 
independent_pairFormation, 
unionElimination, 
because_Cache, 
independent_functionElimination, 
rename, 
inlFormation, 
addLevel, 
dependent_functionElimination, 
orFunctionality, 
cumulativity, 
sqequalRule, 
independent_pairEquality, 
isect_memberEquality, 
equalityTransitivity, 
equalitySymmetry, 
axiomEquality, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[a,b:fset(T)].    (a  \mcup{}  a  \mcap{}  b  =  a)
Date html generated:
2016_05_14-PM-03_40_23
Last ObjectModification:
2015_12_26-PM-06_41_20
Theory : finite!sets
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