Nuprl Lemma : i-approx-rep
∀I:Interval. ∀n:ℕ+. ∀r:ℝ.  ((r ∈ i-approx(I;n)) ⇒ (∃a,b:ℝ. ((a ≤ b) ∧ (i-approx(I;n) = [a, b] ∈ Interval))))
Proof
Definitions occuring in Statement : 
i-approx: i-approx(I;n), 
rccint: [l, u], 
i-member: r ∈ I, 
interval: Interval, 
rleq: x ≤ y, 
real: ℝ, 
nat_plus: ℕ+, 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
implies: P ⇒ Q, 
and: P ∧ Q, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
member: t ∈ T, 
implies: P ⇒ Q, 
prop: ℙ, 
uall: ∀[x:A]. B[x], 
exists: ∃x:A. B[x], 
uimplies: b supposing a, 
and: P ∧ Q, 
cand: A c∧ B, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
icompact: icompact(I), 
interval: Interval, 
i-finite: i-finite(I), 
i-closed: i-closed(I), 
i-nonvoid: i-nonvoid(I), 
isl: isl(x), 
outl: outl(x), 
bnot: ¬bb, 
ifthenelse: if b then t else f fi , 
btrue: tt, 
assert: ↑b, 
bor: p ∨bq, 
bfalse: ff, 
false: False, 
top: Top, 
rccint: [l, u], 
squash: ↓T, 
true: True
Lemmas referenced : 
i-approx-compact, 
i-member_wf, 
i-approx_wf, 
real_wf, 
nat_plus_wf, 
interval_wf, 
equal_wf, 
left-endpoint_wf, 
right-endpoint_wf, 
rleq_wf, 
rccint_wf, 
exists_wf, 
icompact_wf, 
icompact-endpoints-rleq, 
squash_wf, 
true_wf, 
left_endpoint_rccint_lemma, 
right_endpoint_rccint_lemma
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
hypothesis, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
isectElimination, 
equalityTransitivity, 
equalitySymmetry, 
dependent_pairFormation, 
independent_isectElimination, 
because_Cache, 
independent_pairFormation, 
productEquality, 
sqequalRule, 
lambdaEquality, 
productElimination, 
unionElimination, 
voidElimination, 
applyEquality, 
imageElimination, 
isect_memberEquality, 
voidEquality, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed
Latex:
\mforall{}I:Interval.  \mforall{}n:\mBbbN{}\msupplus{}.  \mforall{}r:\mBbbR{}.    ((r  \mmember{}  i-approx(I;n))  {}\mRightarrow{}  (\mexists{}a,b:\mBbbR{}.  ((a  \mleq{}  b)  \mwedge{}  (i-approx(I;n)  =  [a,  b]))))
Date html generated:
2017_10_03-AM-09_34_39
Last ObjectModification:
2017_07_28-AM-07_52_25
Theory : reals
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