Nuprl Lemma : sp-lub-is-bottom
∀[A:ℕ ⟶ Sierpinski]. (lub(n.A[n]) = ⊥ ∈ Sierpinski ⇐⇒ ∀n:ℕ. (A[n] = ⊥ ∈ Sierpinski))
Proof
Definitions occuring in Statement : 
sp-lub: lub(n.A[n]), 
Sierpinski: Sierpinski, 
Sierpinski-bottom: ⊥, 
nat: ℕ, 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
function: x:A ⟶ B[x], 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
implies: P ⇒ Q, 
all: ∀x:A. B[x], 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
rev_implies: P ⇐ Q, 
subtype_rel: A ⊆r B, 
uimplies: b supposing a, 
nat: ℕ, 
so_lambda: λ2x y.t[x; y], 
so_apply: x[s1;s2], 
guard: {T}, 
Sierpinski: Sierpinski, 
prop: ℙ, 
rev_uimplies: rev_uimplies(P;Q), 
uiff: uiff(P;Q), 
cand: A c∧ B, 
sp-lub: lub(n.A[n]), 
Sierpinski-bottom: ⊥, 
quotient: x,y:A//B[x; y], 
or: P ∨ Q, 
decidable: Dec(P), 
false: False, 
not: ¬A, 
fun-equiv: fun-equiv(X;a,b.E[a; b];f;g), 
true: True, 
squash: ↓T, 
bfalse: ff, 
ifthenelse: if b then t else f fi , 
assert: ↑b
Lemmas referenced : 
istype-nat, 
Sierpinski_wf, 
sp-lub_wf, 
Sierpinski-bottom_wf, 
subtype-Sierpinski, 
quotient-function-subtype, 
nat_wf, 
set_subtype_base, 
le_wf, 
istype-int, 
int_subtype_base, 
bool_wf, 
iff_wf, 
equal-wf-T-base, 
two-class-equiv-rel, 
fun-equiv-rel, 
squash_wf, 
equiv_rel_squash, 
subtype_rel_self, 
quotient_wf, 
subtype_rel_transitivity, 
fun-equiv_wf, 
equal-Sierpinski-bottom, 
bfalse_wf, 
quotient-member-eq, 
istype-assert, 
decidable__assert, 
assert_wf, 
decidable__not, 
coded-code-pair, 
assert_functionality_wrt_uiff, 
coded-pair_wf, 
iff_weakening_uiff, 
code-pair_wf, 
sp-lub_wf1, 
equal_wf, 
true_wf, 
istype-universe, 
iff_weakening_equal, 
istype-void
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
independent_pairFormation, 
lambdaFormation_alt, 
hypothesis, 
extract_by_obid, 
equalityIstype, 
universeIsType, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
sqequalRule, 
lambdaEquality_alt, 
applyEquality, 
hypothesisEquality, 
baseClosed, 
sqequalBase, 
equalitySymmetry, 
functionIsType, 
because_Cache, 
productElimination, 
independent_pairEquality, 
dependent_functionElimination, 
axiomEquality, 
functionIsTypeImplies, 
inhabitedIsType, 
independent_isectElimination, 
intEquality, 
natural_numberEquality, 
functionEquality, 
independent_functionElimination, 
closedConclusion, 
equalityTransitivity, 
equalityIsType4, 
equalityIsType1, 
productIsType, 
equalityIsType3, 
pertypeElimination, 
pointwiseFunctionalityForEquality, 
voidElimination, 
unionElimination, 
rename, 
spreadEquality, 
promote_hyp, 
imageElimination, 
instantiate, 
universeEquality, 
imageMemberEquality
Latex:
\mforall{}[A:\mBbbN{}  {}\mrightarrow{}  Sierpinski].  (lub(n.A[n])  =  \mbot{}  \mLeftarrow{}{}\mRightarrow{}  \mforall{}n:\mBbbN{}.  (A[n]  =  \mbot{}))
 Date html generated: 
2019_10_31-AM-06_36_16
 Last ObjectModification: 
2018_12_13-PM-03_00_18
Theory : synthetic!topology
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