Step
*
of Lemma
compact-subinterval
∀I:Interval. ∀J:{J:Interval| icompact(J)} . (J ⊆ I
⇒ (∃n:{n:ℕ+| icompact(i-approx(I;n))} . J ⊆ i-approx(I;n) ))
BY
{ (Auto
THEN (Assert icompact(J) BY
(DVar `J'⋅ THEN Unhide THEN Auto))
THEN (InstLemma `i-member-compact` [⌜J⌝]⋅ THENA Auto)
THEN (InstLemma `icompact-endpoints` [⌜J⌝]⋅ THENA Auto)
THEN (InstLemma `i-member-iff` [⌜I⌝]⋅ THENA Auto)) }
1
1. I : Interval
2. J : {J:Interval| icompact(J)}
3. J ⊆ I
4. icompact(J)
5. ∀r:ℝ. (r ∈ J
⇐⇒ left-endpoint(J)≤r≤right-endpoint(J))
6. (left-endpoint(J) ∈ J) ∧ (right-endpoint(J) ∈ J)
7. ∀r:ℝ. (r ∈ I
⇐⇒ ∃n:ℕ+. (r ∈ i-approx(I;n)))
⊢ ∃n:{n:ℕ+| icompact(i-approx(I;n))} . J ⊆ i-approx(I;n)
Latex:
Latex:
\mforall{}I:Interval. \mforall{}J:\{J:Interval| icompact(J)\} .
(J \msubseteq{} I {}\mRightarrow{} (\mexists{}n:\{n:\mBbbN{}\msupplus{}| icompact(i-approx(I;n))\} . J \msubseteq{} i-approx(I;n) ))
By
Latex:
(Auto
THEN (Assert icompact(J) BY
(DVar `J'\mcdot{} THEN Unhide THEN Auto))
THEN (InstLemma `i-member-compact` [\mkleeneopen{}J\mkleeneclose{}]\mcdot{} THENA Auto)
THEN (InstLemma `icompact-endpoints` [\mkleeneopen{}J\mkleeneclose{}]\mcdot{} THENA Auto)
THEN (InstLemma `i-member-iff` [\mkleeneopen{}I\mkleeneclose{}]\mcdot{} THENA Auto))
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