Nuprl Lemma : real-continuity2-ext
∀a,b:ℝ.
∀f:[a, b] ⟶ℝ
((∀x,y:{x:ℝ| x ∈ [a, b]} . (f x ≠ f y ⇒ x ≠ y))
⇒ (∀k:ℕ+. ∃d:{d:ℝ| r0 < d} . ∀x,y:{x:ℝ| x ∈ [a, b]} . ((|x - y| ≤ d) ⇒ (|(f x) - f y| ≤ (r1/r(k))))))
supposing a ≤ b
Proof
Definitions occuring in Statement :
rfun: I ⟶ℝ,
rccint: [l, u],
i-member: r ∈ I,
rdiv: (x/y),
rneq: x ≠ y,
rleq: x ≤ y,
rless: x < y,
rabs: |x|,
rsub: x - y,
int-to-real: r(n),
real: ℝ,
nat_plus: ℕ+,
uimplies: b supposing a,
all: ∀x:A. B[x],
exists: ∃x:A. B[x],
implies: P ⇒ Q,
set: {x:A| B[x]} ,
apply: f a,
natural_number: $n
Definitions unfolded in proof :
real-continuity-ext,
real-continuity2,
ifthenelse: if b then t else f fi ,
bfalse: ff,
it: ⋅,
btrue: tt,
subtract: n - m,
member: t ∈ T
Lemmas referenced :
real-continuity2,
real-continuity-ext
Rules used in proof :
equalitySymmetry,
equalityTransitivity,
sqequalHypSubstitution,
thin,
sqequalRule,
hypothesis,
extract_by_obid,
instantiate,
cut,
sqequalReflexivity,
computationStep,
sqequalTransitivity,
sqequalSubstitution,
introduction
Latex:
\mforall{}a,b:\mBbbR{}.
\mforall{}f:[a, b] {}\mrightarrow{}\mBbbR{}
((\mforall{}x,y:\{x:\mBbbR{}| x \mmember{} [a, b]\} . (f x \mneq{} f y {}\mRightarrow{} x \mneq{} y))
{}\mRightarrow{} (\mforall{}k:\mBbbN{}\msupplus{}
\mexists{}d:\{d:\mBbbR{}| r0 < d\}
\mforall{}x,y:\{x:\mBbbR{}| x \mmember{} [a, b]\} . ((|x - y| \mleq{} d) {}\mRightarrow{} (|(f x) - f y| \mleq{} (r1/r(k))))))
supposing a \mleq{} b
Date html generated:
2018_05_22-PM-02_11_39
Last ObjectModification:
2018_05_21-AM-00_27_29
Theory : reals
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