Nuprl Lemma : ifun_subtype_3

∀[a,b,c,d:ℝ].  ((a ≤ c) ⇒ (c ≤ d) ⇒ (d ≤ b) ⇒ ({f:[a, b] ⟶ℝ| ifun(f;[a, b])}  ⊆r {f:[c, d] ⟶ℝ| ifun(f;[c, d])} ))


Proof




Definitions occuring in Statement :  ifun: ifun(f;I),  rfun: I ⟶ℝ,  rccint: [l, u],  rleq: x ≤ y,  real: ℝ,  subtype_rel: A ⊆r B,  uall: ∀[x:A]. B[x],  implies: P ⇒ Q,  set: {x:A| B[x]} 
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  implies: P ⇒ Q,  subtype_rel: A ⊆r B,  uimplies: b supposing a,  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  and: P ∧ Q,  prop: ℙ,  guard: {T},  ifun: ifun(f;I),  real-fun: real-fun(f;a;b),  top: Top,  so_lambda: λ2x.t[x],  so_apply: x[s],  cand: A c∧ B
Lemmas referenced :  rfun_subtype_3,  ifun_wf,  rccint_wf,  rccint-icompact,  rfun_wf,  rleq_transitivity,  rleq_wf,  real_wf,  member_rccint_lemma,  left_endpoint_rccint_lemma,  right_endpoint_rccint_lemma,  subtype_rel_sets,  set_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  lambdaFormation,  lambdaEquality,  setElimination,  thin,  rename,  dependent_set_memberEquality,  hypothesisEquality,  applyEquality,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  independent_functionElimination,  hypothesis,  sqequalRule,  independent_isectElimination,  dependent_functionElimination,  productElimination,  setEquality,  because_Cache,  axiomEquality,  isect_memberEquality,  voidElimination,  voidEquality,  productEquality,  independent_pairFormation

Latex:
\mforall{}[a,b,c,d:\mBbbR{}].
    ((a  \mleq{}  c)
    {}\mRightarrow{}  (c  \mleq{}  d)
    {}\mRightarrow{}  (d  \mleq{}  b)
    {}\mRightarrow{}  (\{f:[a,  b]  {}\mrightarrow{}\mBbbR{}|  ifun(f;[a,  b])\}    \msubseteq{}r  \{f:[c,  d]  {}\mrightarrow{}\mBbbR{}|  ifun(f;[c,  d])\}  ))



Date html generated: 2016_10_26-AM-09_48_45
Last ObjectModification: 2016_08_20-PM-07_30_31

Theory : reals


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