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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