Nuprl Lemma : sp-join-idemp
∀[x:Sierpinski]. (x ∨ x = x ∈ Sierpinski)
Proof
Definitions occuring in Statement : 
sp-join: f ∨ g, 
Sierpinski: Sierpinski, 
uall: ∀[x:A]. B[x], 
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, 
iff: P ⇐⇒ Q, 
implies: P ⇒ Q, 
prop: ℙ, 
rev_implies: P ⇐ Q
Lemmas referenced : 
Sierpinski-equal, 
sp-join_wf, 
Sierpinski_wf, 
equal-wf-T-base, 
iff_wf, 
sp-join-is-bottom
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
productElimination, 
independent_isectElimination, 
independent_pairFormation, 
lambdaFormation, 
productEquality, 
baseClosed, 
because_Cache, 
addLevel, 
impliesFunctionality, 
independent_functionElimination
Latex:
\mforall{}[x:Sierpinski].  (x  \mvee{}  x  =  x)
Date html generated:
2019_10_31-AM-07_18_39
Last ObjectModification:
2017_07_28-AM-09_12_21
Theory : synthetic!topology
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