Nuprl Lemma : infn-property

I:{I:Interval| icompact(I)} . ∀n:ℕ. ∀f:{f:I^n ⟶ ℝ| ∀a,b:I^n.  (req-vec(n;a;b)  ((f a) (f b)))} . ∀e:{e:ℝr0 < e} \000C.
  ∃x:I^n. ((f x) ≤ ((infn(n;I) f) e))


Proof




Definitions occuring in Statement :  infn: infn(n;I) interval-vec: I^n req-vec: req-vec(n;x;y) icompact: icompact(I) interval: Interval rleq: x ≤ y rless: x < y req: y radd: b int-to-real: r(n) real: nat: all: x:A. B[x] exists: x:A. B[x] implies:  Q set: {x:A| B[x]}  apply: a function: x:A ⟶ B[x] natural_number: $n
Definitions unfolded in proof :  all: x:A. B[x] member: t ∈ T uall: [x:A]. B[x] prop: nat: le: A ≤ B and: P ∧ Q less_than': less_than'(a;b) not: ¬A implies:  Q false: False interval-vec: I^n decidable: Dec(P) or: P ∨ Q uimplies: supposing a satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] subtype_rel: A ⊆B so_lambda: λ2x.t[x] so_apply: x[s] guard: {T} squash: T sq_stable: SqStable(P) rev_uimplies: rev_uimplies(P;Q) uiff: uiff(P;Q) infn: infn(n;I) lelt: i ≤ j < k int_seg: {i..j-} real-vec: ^n top: Top req_int_terms: t1 ≡ t2 sq_type: SQType(T) subtract: m cand: c∧ B nat_plus: + assert: b ifthenelse: if then else fi  bfalse: ff iff: ⇐⇒ Q rev_implies:  Q req-vec: req-vec(n;x;y) real-vec-extend: a++z bool: 𝔹 unit: Unit it: btrue: tt bnot: ¬bb inf: inf(A) b rneq: x ≠ y less_than: a < b true: True rrange: f[x](x∈I) rset-member: x ∈ A rdiv: (x/y) rless: x < y sq_exists: x:A [B[x]] rge: x ≥ y

Latex:
\mforall{}I:\{I:Interval|  icompact(I)\}  .  \mforall{}n:\mBbbN{}.  \mforall{}f:\{f:I\^{}n  {}\mrightarrow{}  \mBbbR{}|  \mforall{}a,b:I\^{}n.    (req-vec(n;a;b)  {}\mRightarrow{}  ((f  a)  =  (f  b)))\}\000C  .
\mforall{}e:\{e:\mBbbR{}|  r0  <  e\}  .
    \mexists{}x:I\^{}n.  ((f  x)  \mleq{}  ((infn(n;I)  f)  +  e))



Date html generated: 2020_05_20-PM-00_40_32
Last ObjectModification: 2020_01_06-PM-11_01_55

Theory : reals


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