Nuprl Lemma : f-subset-union
∀[A:Type]. ∀[eqa:EqDecider(A)]. ∀[x,y:fset(A)].  x ⊆ x ⋃ y
Proof
Definitions occuring in Statement : 
fset-union: x ⋃ y
, 
f-subset: xs ⊆ ys
, 
fset: fset(T)
, 
deq: EqDecider(T)
, 
uall: ∀[x:A]. B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
f-subset: xs ⊆ ys
, 
all: ∀x:A. B[x]
, 
uimplies: b supposing a
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
, 
or: P ∨ Q
, 
prop: ℙ
Lemmas referenced : 
member-fset-union, 
fset-member_wf, 
fset-member_witness, 
fset-union_wf, 
fset_wf, 
deq_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
lambdaFormation, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
because_Cache, 
dependent_functionElimination, 
hypothesisEquality, 
hypothesis, 
productElimination, 
independent_functionElimination, 
inlFormation, 
sqequalRule, 
lambdaEquality, 
isect_memberEquality, 
equalityTransitivity, 
equalitySymmetry, 
universeEquality
Latex:
\mforall{}[A:Type].  \mforall{}[eqa:EqDecider(A)].  \mforall{}[x,y:fset(A)].    x  \msubseteq{}  x  \mcup{}  y
Date html generated:
2016_05_14-PM-03_38_41
Last ObjectModification:
2015_12_26-PM-06_42_00
Theory : finite!sets
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