Nuprl Lemma : IVT-strictly-increasing-open
∀a:ℝ. ∀b:{b:ℝ| a < b} . ∀f:[a, b] ⟶ℝ.
  f[x] strictly-increasing for x ∈ (a, b) 
⇒ (∀c:ℝ. ((f(a) < c) 
⇒ (c < f(b)) 
⇒ (∃x:ℝ. ((x ∈ (a, b)) ∧ (f(x) = c))))) 
  supposing ∀x,y:{x:ℝ| x ∈ [a, b]} .  ((x = y) 
⇒ (f[x] = f[y]))
Proof
Definitions occuring in Statement : 
strictly-increasing-on-interval: f[x] strictly-increasing for x ∈ I
, 
r-ap: f(x)
, 
rfun: I ⟶ℝ
, 
rooint: (l, u)
, 
rccint: [l, u]
, 
i-member: r ∈ I
, 
rless: x < y
, 
req: x = y
, 
real: ℝ
, 
uimplies: b supposing a
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
set: {x:A| B[x]} 
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
implies: P 
⇒ Q
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
rfun: I ⟶ℝ
, 
subinterval: I ⊆ J 
, 
top: Top
, 
and: P ∧ Q
, 
cand: A c∧ B
, 
guard: {T}
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
label: ...$L... t
, 
subtype_rel: A ⊆r B
, 
i-member: r ∈ I
, 
rccint: [l, u]
, 
rooint: (l, u)
, 
locally-non-constant: locally-non-constant(f;a;b;c)
, 
strictly-increasing-on-interval: f[x] strictly-increasing for x ∈ I
, 
or: P ∨ Q
, 
exists: ∃x:A. B[x]
, 
rneq: x ≠ y
, 
r-ap: f(x)
Lemmas referenced : 
IVT-locally-non-constant-open, 
req_witness, 
member_rooint_lemma, 
istype-void, 
member_rccint_lemma, 
rleq_weakening_rless, 
rless_wf, 
strictly-increasing-on-interval_wf, 
rooint_wf, 
subtype_rel_sets_simple, 
real_wf, 
i-member_wf, 
rccint_wf, 
req_wf, 
rfun_wf, 
rless_transitivity1, 
rless_transitivity2, 
rleq_wf, 
rless-cases, 
rleq_weakening_equal, 
r-ap_wf, 
rleq_transitivity, 
rneq_wf
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
hypothesis, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
isect_memberFormation_alt, 
sqequalRule, 
lambdaEquality_alt, 
isectElimination, 
applyEquality, 
because_Cache, 
independent_functionElimination, 
functionIsTypeImplies, 
inhabitedIsType, 
rename, 
independent_isectElimination, 
isect_memberEquality_alt, 
voidElimination, 
productElimination, 
independent_pairFormation, 
setElimination, 
productIsType, 
universeIsType, 
setIsType, 
functionIsType, 
dependent_set_memberEquality_alt, 
unionElimination, 
dependent_pairFormation_alt, 
inlFormation_alt, 
inrFormation_alt
Latex:
\mforall{}a:\mBbbR{}.  \mforall{}b:\{b:\mBbbR{}|  a  <  b\}  .  \mforall{}f:[a,  b]  {}\mrightarrow{}\mBbbR{}.
    f[x]  strictly-increasing  for  x  \mmember{}  (a,  b)
    {}\mRightarrow{}  (\mforall{}c:\mBbbR{}.  ((f(a)  <  c)  {}\mRightarrow{}  (c  <  f(b))  {}\mRightarrow{}  (\mexists{}x:\mBbbR{}.  ((x  \mmember{}  (a,  b))  \mwedge{}  (f(x)  =  c))))) 
    supposing  \mforall{}x,y:\{x:\mBbbR{}|  x  \mmember{}  [a,  b]\}  .    ((x  =  y)  {}\mRightarrow{}  (f[x]  =  f[y]))
Date html generated:
2019_10_30-AM-09_09_49
Last ObjectModification:
2019_04_02-PM-00_03_33
Theory : reals
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