Nuprl Lemma : l-union-contained
∀[T:Type]. ∀eq:EqDecider(T). ∀as,bs,cs:T List.  (as ⋃ bs ⊆ cs 
⇐⇒ as ⊆ cs ∧ bs ⊆ cs)
Proof
Definitions occuring in Statement : 
l-union: as ⋃ bs
, 
l_contains: A ⊆ B
, 
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_contains: A ⊆ B
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
or: P ∨ Q
, 
prop: ℙ
, 
guard: {T}
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
l_member_wf, 
all_wf, 
or_wf, 
and_wf, 
member-union, 
l-union_wf, 
iff_wf, 
l_all_iff, 
l_all_wf, 
list_wf, 
deq_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
independent_pairFormation, 
hypothesis, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
inlFormation, 
lemma_by_obid, 
isectElimination, 
sqequalRule, 
inrFormation, 
because_Cache, 
lambdaEquality, 
functionEquality, 
productElimination, 
unionElimination, 
addLevel, 
impliesFunctionality, 
allFunctionality, 
allLevelFunctionality, 
impliesLevelFunctionality, 
cumulativity, 
productEquality, 
setElimination, 
rename, 
setEquality, 
andLevelFunctionality, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}eq:EqDecider(T).  \mforall{}as,bs,cs:T  List.    (as  \mcup{}  bs  \msubseteq{}  cs  \mLeftarrow{}{}\mRightarrow{}  as  \msubseteq{}  cs  \mwedge{}  bs  \msubseteq{}  cs)
Date html generated:
2016_05_14-PM-03_24_47
Last ObjectModification:
2015_12_26-PM-06_22_04
Theory : decidable!equality
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