Nuprl Lemma : sp-join_wf
∀[f,g:Sierpinski].  (f ∨ g ∈ Sierpinski)
Proof
Definitions occuring in Statement : 
sp-join: f ∨ g, 
Sierpinski: Sierpinski, 
uall: ∀[x:A]. B[x], 
member: t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
Sierpinski: Sierpinski, 
quotient: x,y:A//B[x; y], 
and: P ∧ Q, 
sp-join: f ∨ g, 
so_lambda: λ2x y.t[x; y], 
so_apply: x[s1;s2], 
uimplies: b supposing a, 
iff: P ⇐⇒ Q, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
prop: ℙ, 
rev_implies: P ⇐ Q, 
uiff: uiff(P;Q), 
not: ¬A, 
false: False, 
or: P ∨ Q, 
guard: {T}, 
assert: ↑b, 
ifthenelse: if b then t else f fi , 
bor: p ∨bq, 
Sierpinski-bottom: ⊥, 
bfalse: ff
Lemmas referenced : 
Sierpinski_wf, 
quotient-member-eq, 
nat_wf, 
bool_wf, 
iff_wf, 
equal-wf-T-base, 
two-class-equiv-rel, 
Sierpinski-bottom_wf, 
bor_wf, 
equal-wf-base, 
equal-Sierpinski-bottom, 
assert_wf, 
assert_of_bor, 
or_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalHypSubstitution, 
pointwiseFunctionalityForEquality, 
extract_by_obid, 
hypothesis, 
sqequalRule, 
pertypeElimination, 
productElimination, 
thin, 
isectElimination, 
functionEquality, 
lambdaEquality, 
because_Cache, 
hypothesisEquality, 
baseClosed, 
independent_isectElimination, 
dependent_functionElimination, 
applyEquality, 
independent_functionElimination, 
independent_pairFormation, 
lambdaFormation, 
productEquality, 
equalityTransitivity, 
equalitySymmetry, 
axiomEquality, 
isect_memberEquality, 
hyp_replacement, 
applyLambdaEquality, 
functionExtensionality, 
voidElimination, 
allFunctionality, 
promote_hyp, 
inlFormation, 
inrFormation, 
rename
Latex:
\mforall{}[f,g:Sierpinski].    (f  \mvee{}  g  \mmember{}  Sierpinski)
 Date html generated: 
2019_10_31-AM-06_35_48
 Last ObjectModification: 
2017_07_28-AM-09_11_59
Theory : synthetic!topology
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