Nuprl Lemma : rational-IVT-ext
∀a,b:ℝ. ∀f:(ℤ × ℕ+) ⟶ (ℤ × ℕ+).
  ∀[g:{x:ℝ| x ∈ [a, b]}  ⟶ ℝ]
    ∃c:{c:ℝ| c ∈ (a, b)}  [(g[c] = r0)] 
    supposing (a < b)
    ∧ ((g[a] * g[b]) < r0)
    ∧ (∀x,y:{x:ℝ| x ∈ [a, b]} .  ((x = y) 
⇒ (g[x] = g[y])))
    ∧ (∀r:ℤ × ℕ+. ((ratreal(r) ∈ [a, b]) 
⇒ (g[ratreal(r)] = ratreal(f[r]))))
Proof
Definitions occuring in Statement : 
ratreal: ratreal(r)
, 
rooint: (l, u)
, 
rccint: [l, u]
, 
i-member: r ∈ I
, 
rless: x < y
, 
req: x = y
, 
rmul: a * b
, 
int-to-real: r(n)
, 
real: ℝ
, 
nat_plus: ℕ+
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
sq_exists: ∃x:A [B[x]]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
set: {x:A| B[x]} 
, 
function: x:A ⟶ B[x]
, 
product: x:A × B[x]
, 
natural_number: $n
, 
int: ℤ
Definitions unfolded in proof : 
member: t ∈ T
, 
so_apply: x[s]
, 
subtract: n - m
, 
pi1: fst(t)
, 
ratreal: ratreal(r)
, 
rat-to-real: r(a/b)
, 
int-rdiv: (a)/k1
, 
int-to-real: r(n)
, 
rlessw: rlessw(x;y)
, 
quick-find: quick-find(p;n)
, 
ifthenelse: if b then t else f fi 
, 
int-rat-mul: int-rat-mul(n;x)
, 
so_lambda: λ2x.t[x]
, 
rational_fun_zero: rational_fun_zero(f;a;b)
, 
rational-IVT, 
sq_stable__and, 
sq_stable__rless, 
rleq_functionality, 
rat-zero-cases, 
sq_stable__rleq, 
uall: ∀[x:A]. B[x]
, 
so_lambda: so_lambda(x,y,z,w.t[x; y; z; w])
, 
so_apply: x[s1;s2;s3;s4]
, 
so_lambda: λ2x y.t[x; y]
, 
top: Top
, 
so_apply: x[s1;s2]
, 
uimplies: b supposing a
Lemmas referenced : 
rational-IVT, 
lifting-strict-callbyvalue, 
istype-void, 
strict4-spread, 
lifting-strict-decide, 
strict4-decide, 
lifting-strict-spread, 
lifting-strict-less, 
sq_stable__and, 
sq_stable__rless, 
rleq_functionality, 
rat-zero-cases, 
sq_stable__rleq
Rules used in proof : 
introduction, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
cut, 
instantiate, 
extract_by_obid, 
hypothesis, 
sqequalRule, 
thin, 
sqequalHypSubstitution, 
equalityTransitivity, 
equalitySymmetry, 
isectElimination, 
baseClosed, 
isect_memberEquality_alt, 
voidElimination, 
independent_isectElimination
Latex:
\mforall{}a,b:\mBbbR{}.  \mforall{}f:(\mBbbZ{}  \mtimes{}  \mBbbN{}\msupplus{})  {}\mrightarrow{}  (\mBbbZ{}  \mtimes{}  \mBbbN{}\msupplus{}).
    \mforall{}[g:\{x:\mBbbR{}|  x  \mmember{}  [a,  b]\}    {}\mrightarrow{}  \mBbbR{}]
        \mexists{}c:\{c:\mBbbR{}|  c  \mmember{}  (a,  b)\}    [(g[c]  =  r0)] 
        supposing  (a  <  b)
        \mwedge{}  ((g[a]  *  g[b])  <  r0)
        \mwedge{}  (\mforall{}x,y:\{x:\mBbbR{}|  x  \mmember{}  [a,  b]\}  .    ((x  =  y)  {}\mRightarrow{}  (g[x]  =  g[y])))
        \mwedge{}  (\mforall{}r:\mBbbZ{}  \mtimes{}  \mBbbN{}\msupplus{}.  ((ratreal(r)  \mmember{}  [a,  b])  {}\mRightarrow{}  (g[ratreal(r)]  =  ratreal(f[r]))))
Date html generated:
2019_10_30-AM-10_05_07
Last ObjectModification:
2019_01_14-PM-00_30_53
Theory : reals
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