Nuprl Lemma : IVT-strictly-increasing-open

a:ℝ. ∀b:{b:ℝa < 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:ℝx ∈ [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: y real: uimplies: supposing a so_apply: x[s] all: x:A. B[x] exists: x:A. B[x] implies:  Q and: P ∧ Q set: {x:A| B[x]} 
Definitions unfolded in proof :  all: x:A. B[x] member: t ∈ T uimplies: supposing a implies:  Q uall: [x:A]. B[x] so_apply: x[s] rfun: I ⟶ℝ subinterval: I ⊆  top: Top and: P ∧ Q cand: c∧ B guard: {T} prop: so_lambda: λ2x.t[x] label: ...$L... t subtype_rel: A ⊆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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