Nuprl Lemma : cantor-to-interval-onto-common

a,b:ℝ.
  ∀x,y:ℝ.
    ((x ∈ [a, b])
     (y ∈ [a, b])
     (∀n:ℕ
          ((|x y| ≤ (2^n a)/6 3^n)
           (∃f,g:ℕ ⟶ 𝔹
               (((cantor-to-interval(a;b;f) x) ∧ (cantor-to-interval(a;b;g) y)) ∧ (f g ∈ (ℕn ⟶ 𝔹))))))) 
  supposing a < b


Proof




Definitions occuring in Statement :  cantor-to-interval: cantor-to-interval(a;b;f) rccint: [l, u] i-member: r ∈ I rleq: x ≤ y rless: x < y rabs: |x| int-rdiv: (a)/k1 int-rmul: k1 a rsub: y req: y real: exp: i^n int_seg: {i..j-} nat: bool: 𝔹 uimplies: supposing a all: x:A. B[x] exists: x:A. B[x] implies:  Q and: P ∧ Q function: x:A ⟶ B[x] multiply: m natural_number: $n equal: t ∈ T
Definitions unfolded in proof :  all: x:A. B[x] uimplies: supposing a implies:  Q member: t ∈ T uall: [x:A]. B[x] int_nzero: -o true: True nequal: a ≠ b ∈  not: ¬A sq_type: SQType(T) guard: {T} false: False nat: rless: x < y sq_exists: x:A [B[x]] nat_plus: + ge: i ≥  decidable: Dec(P) or: P ∨ Q satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] and: P ∧ Q prop: subtype_rel: A ⊆B int_seg: {i..j-} lelt: i ≤ j < k le: A ≤ B so_lambda: λ2x.t[x] so_apply: x[s] less_than: a < b squash: T pi1: fst(t) pi2: snd(t) less_than': less_than'(a;b) cand: c∧ B iff: ⇐⇒ Q rev_implies:  Q uiff: uiff(P;Q) subtract: m sq_stable: SqStable(P) cantor-interval: cantor-interval(a;b;f;n) bool: 𝔹 unit: Unit it: btrue: tt bfalse: ff bnot: ¬bb ifthenelse: if then else fi  assert: b rneq: x ≠ y rev_uimplies: rev_uimplies(P;Q) rge: x ≥ y top: Top real: rdiv: (x/y) req_int_terms: t1 ≡ t2 rccint: [l, u] i-member: r ∈ I lt_int: i <j

Latex:
\mforall{}a,b:\mBbbR{}.
    \mforall{}x,y:\mBbbR{}.
        ((x  \mmember{}  [a,  b])
        {}\mRightarrow{}  (y  \mmember{}  [a,  b])
        {}\mRightarrow{}  (\mforall{}n:\mBbbN{}
                    ((|x  -  y|  \mleq{}  (2\^{}n  *  b  -  a)/6  *  3\^{}n)
                    {}\mRightarrow{}  (\mexists{}f,g:\mBbbN{}  {}\mrightarrow{}  \mBbbB{}
                              (((cantor-to-interval(a;b;f)  =  x)  \mwedge{}  (cantor-to-interval(a;b;g)  =  y))  \mwedge{}  (f  =  g)))))) 
    supposing  a  <  b



Date html generated: 2020_05_20-PM-00_09_15
Last ObjectModification: 2020_01_02-PM-01_56_58

Theory : reals


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