Nuprl Lemma : union-ss_wf
∀[ss1,ss2:SeparationSpace].  (ss1 + ss2 ∈ SeparationSpace)
Proof
Definitions occuring in Statement : 
union-ss: ss1 + ss2, 
separation-space: SeparationSpace, 
uall: ∀[x:A]. B[x], 
member: t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
union-ss: ss1 + ss2, 
all: ∀x:A. B[x], 
not: ¬A, 
implies: P ⇒ Q, 
false: False, 
union-sep: union-sep(ss1;ss2;p;q), 
prop: ℙ, 
subtype_rel: A ⊆r B, 
or: P ∨ Q, 
true: True, 
separation-space: SeparationSpace, 
record+: record+, 
record-select: r.x, 
eq_atom: x =a y, 
ifthenelse: if b then t else f fi , 
btrue: tt, 
ss-sep: x # y, 
ss-point: Point(ss), 
uimplies: b supposing a
Lemmas referenced : 
mk-ss_wf, 
ss-point_wf, 
union-sep_wf, 
ss-sep-irrefl, 
subtype_rel_self, 
istype-void, 
separation-space_wf, 
istype-true, 
ss-sep_wf, 
not_wf, 
subtype_rel_function
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
unionEquality, 
hypothesisEquality, 
hypothesis, 
dependent_set_memberEquality_alt, 
lambdaEquality_alt, 
inhabitedIsType, 
unionIsType, 
universeIsType, 
sqequalRule, 
lambdaFormation_alt, 
unionElimination, 
independent_functionElimination, 
voidElimination, 
because_Cache, 
functionIsType, 
applyEquality, 
instantiate, 
universeEquality, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
inlEquality_alt, 
closedConclusion, 
natural_numberEquality, 
inrEquality_alt, 
dependentIntersectionElimination, 
dependentIntersectionEqElimination, 
tokenEquality, 
setEquality, 
functionEquality, 
cumulativity, 
functionExtensionality, 
independent_isectElimination
Latex:
\mforall{}[ss1,ss2:SeparationSpace].    (ss1  +  ss2  \mmember{}  SeparationSpace)
Date html generated:
2019_10_31-AM-07_27_03
Last ObjectModification:
2019_09_19-PM-04_11_40
Theory : constructive!algebra
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