Nuprl Lemma : range_inf_functionality

I:{I:Interval| icompact(I)} . ∀f:{x:ℝx ∈ I}  ⟶ ℝ.
  ∀g:{x:ℝx ∈ I}  ⟶ ℝinf{f[x] x ∈ I} inf{g[x] x ∈ I} supposing ∀x:{x:ℝx ∈ I} (f[x] g[x]) 
  supposing ∀x,y:{x:ℝx ∈ I} .  ((x y)  (f[x] f[y]))


Proof




Definitions occuring in Statement :  range_inf: inf{f[x] x ∈ I} icompact: icompact(I) i-member: r ∈ I interval: Interval req: y real: uimplies: supposing a so_apply: x[s] all: x:A. B[x] implies:  Q set: {x:A| B[x]}  function: x:A ⟶ B[x]
Definitions unfolded in proof :  all: x:A. B[x] uimplies: supposing a implies:  Q member: t ∈ T and: P ∧ Q cand: c∧ B uall: [x:A]. B[x] so_apply: x[s] uiff: uiff(P;Q) rev_uimplies: rev_uimplies(P;Q) guard: {T} prop: so_lambda: λ2x.t[x] inf: inf(A) b lower-bound: lower-bound(A;b) rrange: f[x](x∈I) rset-member: x ∈ A exists: x:A. B[x]

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



Date html generated: 2020_05_20-PM-00_18_41
Last ObjectModification: 2020_01_03-PM-03_04_29

Theory : reals


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