Nuprl Lemma : IVT-from-connected

u,v:ℝ. ∀f:[u, v] ⟶ℝ.
  ((u ≤ v)
   (∀x,y:{x:ℝx ∈ [u, v]} .  ((x y)  (f(x) f(y))))
   (f(u) < r0)
   (r0 < f(v))
   (∀e:{e:ℝr0 < e} . ∃c:{c:ℝc ∈ [u, v]} (|f(c)| < e)))


Proof




Definitions occuring in Statement :  r-ap: f(x) rfun: I ⟶ℝ rccint: [l, u] i-member: r ∈ I rleq: x ≤ y rless: x < y rabs: |x| req: y int-to-real: r(n) real: all: x:A. B[x] exists: x:A. B[x] implies:  Q set: {x:A| B[x]}  natural_number: $n
Definitions unfolded in proof :  iff: ⇐⇒ Q or: P ∨ Q not: ¬A false: False req_int_terms: t1 ≡ t2 rgt: x > y rge: x ≥ y rev_implies:  Q uiff: uiff(P;Q) cand: c∧ B exists: x:A. B[x] guard: {T} squash: T sq_stable: SqStable(P) top: Top and: P ∧ Q rccint: [l, u] i-member: r ∈ I so_apply: x[s] uimplies: supposing a prop: so_lambda: λ2x.t[x] uall: [x:A]. B[x] connected: Connected(X) implies:  Q member: t ∈ T all: x:A. B[x]
Lemmas referenced :  rabs_wf rabs-rless-iff rless-cases real_term_value_minus_lemma real_term_value_const_lemma real_term_value_var_lemma real_term_value_sub_lemma real_polynomial_null rless_functionality_wrt_implies req-iff-rsub-is-0 itermMinus_wf itermConstant_wf itermVar_wf itermSubtract_wf rsub_wf rless-implies-rless rleq_weakening_rless rfun_wf rleq_wf req_wf all_wf rleq_weakening_equal int-to-real_wf set_wf rless_transitivity1 req_inversion sq_stable__i-member rleq_weakening rless_transitivity2 sq_stable__rleq member_rccint_lemma sq_stable__rless rminus_wf r-ap_wf rless_wf real_wf rccint_wf i-member_wf closed-interval-connected
Rules used in proof :  inlFormation inrFormation unionElimination intEquality int_eqEquality approximateComputation productEquality dependent_set_memberEquality dependent_pairFormation functionEquality natural_numberEquality imageElimination baseClosed imageMemberEquality productElimination voidEquality voidElimination isect_memberEquality independent_pairFormation independent_functionElimination because_Cache setEquality independent_isectElimination rename setElimination lambdaEquality sqequalRule isectElimination hypothesisEquality thin dependent_functionElimination sqequalHypSubstitution hypothesis lambdaFormation sqequalReflexivity computationStep sqequalTransitivity sqequalSubstitution extract_by_obid introduction cut

Latex:
\mforall{}u,v:\mBbbR{}.  \mforall{}f:[u,  v]  {}\mrightarrow{}\mBbbR{}.
    ((u  \mleq{}  v)
    {}\mRightarrow{}  (\mforall{}x,y:\{x:\mBbbR{}|  x  \mmember{}  [u,  v]\}  .    ((x  =  y)  {}\mRightarrow{}  (f(x)  =  f(y))))
    {}\mRightarrow{}  (f(u)  <  r0)
    {}\mRightarrow{}  (r0  <  f(v))
    {}\mRightarrow{}  (\mforall{}e:\{e:\mBbbR{}|  r0  <  e\}  .  \mexists{}c:\{c:\mBbbR{}|  c  \mmember{}  [u,  v]\}  .  (|f(c)|  <  e)))



Date html generated: 2018_05_22-PM-02_16_48
Last ObjectModification: 2018_05_21-AM-00_31_50

Theory : reals


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