Nuprl Lemma : sp-meet-is-top
∀[x,y:Sierpinski].  (x ∧ y = ⊤ ∈ Sierpinski 
⇐⇒ (x = ⊤ ∈ Sierpinski) ∧ (y = ⊤ ∈ Sierpinski))
Proof
Definitions occuring in Statement : 
sp-meet: f ∧ g
, 
Sierpinski: Sierpinski
, 
Sierpinski-top: ⊤
, 
uall: ∀[x:A]. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
Sierpinski: Sierpinski
, 
quotient: x,y:A//B[x; y]
, 
prop: ℙ
, 
rev_implies: P 
⇐ Q
, 
sp-meet: f ∧ g
, 
cand: A c∧ B
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
uimplies: b supposing a
, 
all: ∀x:A. B[x]
, 
squash: ↓T
, 
true: True
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
Sierpinski-bottom: ⊥
, 
bfalse: ff
, 
band: p ∧b q
, 
ifthenelse: if b then t else f fi 
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
top: Top
, 
false: False
, 
Sierpinski-top: ⊤
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
rev_uimplies: rev_uimplies(P;Q)
, 
assert: ↑b
, 
nat: ℕ
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
not: ¬A
, 
coded-pair: coded-pair(m)
, 
code-pair: code-pair(a;b)
, 
triangular-num: t(n)
, 
tsqrt: tsqrt(n)
, 
isqrt: isqrt(x)
, 
integer-sqrt-ext, 
genrec-ap: genrec-ap, 
le_int: i ≤z j
, 
bnot: ¬bb
, 
lt_int: i <z j
, 
subtract: n - m
Lemmas referenced : 
Sierpinski-unequal-1, 
Sierpinski_wf, 
equal-wf-base, 
iff_wf, 
equal-wf-T-base, 
nat_wf, 
bool_wf, 
sp-meet_wf, 
quotient-member-eq, 
two-class-equiv-rel, 
Sierpinski-bottom_wf, 
equal_wf, 
coded-pair_wf, 
band_wf, 
squash_wf, 
true_wf, 
iff_weakening_equal, 
spread_to_pi12, 
top_wf, 
subtype_rel_product, 
bfalse_wf, 
member_wf, 
band_ff_simp, 
btrue_wf, 
equal-Sierpinski-bottom, 
code-pair_wf, 
false_wf, 
le_wf, 
assert_of_bnot, 
integer-sqrt-ext
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
productElimination, 
thin, 
isect_memberFormation, 
independent_pairFormation, 
lambdaFormation, 
pointwiseFunctionalityForEquality, 
hypothesis, 
sqequalRule, 
pertypeElimination, 
productEquality, 
isectElimination, 
because_Cache, 
hypothesisEquality, 
equalityTransitivity, 
equalitySymmetry, 
baseClosed, 
functionEquality, 
equalityElimination, 
independent_pairEquality, 
lambdaEquality, 
dependent_functionElimination, 
axiomEquality, 
isect_memberEquality, 
independent_isectElimination, 
independent_functionElimination, 
applyEquality, 
imageElimination, 
equalityUniverse, 
levelHypothesis, 
spreadEquality, 
functionExtensionality, 
natural_numberEquality, 
imageMemberEquality, 
voidElimination, 
voidEquality, 
universeEquality, 
dependent_set_memberEquality
Latex:
\mforall{}[x,y:Sierpinski].    (x  \mwedge{}  y  =  \mtop{}  \mLeftarrow{}{}\mRightarrow{}  (x  =  \mtop{})  \mwedge{}  (y  =  \mtop{}))
Date html generated:
2019_10_31-AM-06_35_51
Last ObjectModification:
2017_07_28-AM-09_12_00
Theory : synthetic!topology
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