Nuprl Lemma : strict-increasing-implies-inv-strict-increasing

[I:Interval]. ∀[f:I ⟶ℝ].
  (∀x,y:{x:ℝx ∈ I} .  (((f x) < (f y))  (x < y))) supposing 
     ((∀x,y:{x:ℝx ∈ I} .  ((x < y)  ((f x) < (f y)))) and 
     (∀x,y:{x:ℝx ∈ I} .  ((x y)  ((f x) (f y)))))


Proof




Definitions occuring in Statement :  rfun: I ⟶ℝ i-member: r ∈ I interval: Interval rless: x < y req: y real: uimplies: supposing a uall: [x:A]. B[x] all: x:A. B[x] implies:  Q set: {x:A| B[x]}  apply: a
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T uimplies: supposing a all: x:A. B[x] implies:  Q rfun: I ⟶ℝ prop: sq_stable: SqStable(P) squash: T so_lambda: λ2x.t[x] so_apply: x[s] rneq: x ≠ y or: P ∨ Q guard: {T} false: False
Lemmas referenced :  real-fun-implies-sfun-general req_witness i-member_wf req_wf real_wf sq_stable__rless rless_wf set_wf all_wf rfun_wf interval_wf rless_transitivity2 rleq_weakening_rless rless_irreflexivity
Rules used in proof :  cut introduction extract_by_obid sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation hypothesis sqequalHypSubstitution isectElimination thin hypothesisEquality sqequalRule lambdaEquality dependent_functionElimination applyEquality setElimination rename dependent_set_memberEquality because_Cache independent_functionElimination setEquality independent_isectElimination lambdaFormation imageMemberEquality baseClosed imageElimination functionEquality inlFormation unionElimination voidElimination

Latex:
\mforall{}[I:Interval].  \mforall{}[f:I  {}\mrightarrow{}\mBbbR{}].
    (\mforall{}x,y:\{x:\mBbbR{}|  x  \mmember{}  I\}  .    (((f  x)  <  (f  y))  {}\mRightarrow{}  (x  <  y)))  supposing 
          ((\mforall{}x,y:\{x:\mBbbR{}|  x  \mmember{}  I\}  .    ((x  <  y)  {}\mRightarrow{}  ((f  x)  <  (f  y))))  and 
          (\mforall{}x,y:\{x:\mBbbR{}|  x  \mmember{}  I\}  .    ((x  =  y)  {}\mRightarrow{}  ((f  x)  =  (f  y)))))



Date html generated: 2017_10_03-AM-09_57_15
Last ObjectModification: 2017_08_31-PM-01_21_40

Theory : reals


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