Nuprl Lemma : close-reals-iff

[x,y:ℝ]. ∀[k:ℕ+].  uiff(|x y| ≤ (r1/r(k));∀m:ℕ+((|(x m) m| k) ≤ ((4 k) (2 m))))


Proof




Definitions occuring in Statement :  rdiv: (x/y) rleq: x ≤ y rabs: |x| rsub: y int-to-real: r(n) real: absval: |i| nat_plus: + uiff: uiff(P;Q) uall: [x:A]. B[x] le: A ≤ B all: x:A. B[x] apply: a multiply: m subtract: m add: m natural_number: $n
Definitions unfolded in proof :  subtype_rel: A ⊆B real: rnonneg: rnonneg(x) rleq: x ≤ y prop: false: False exists: x:A. B[x] satisfiable_int_formula: satisfiable_int_formula(fmla) not: ¬A decidable: Dec(P) implies:  Q rev_implies:  Q iff: ⇐⇒ Q or: P ∨ Q guard: {T} rneq: x ≠ y nat_plus: + le: A ≤ B all: x:A. B[x] uimplies: supposing a and: P ∧ Q uiff: uiff(P;Q) member: t ∈ T uall: [x:A]. B[x] rge: x ≥ y rev_uimplies: rev_uimplies(P;Q) rdiv: (x/y) req_int_terms: t1 ≡ t2 less_than': less_than'(a;b) rational-approx: (x within 1/n) nequal: a ≠ b ∈  int_nzero: -o sq_type: SQType(T) so_apply: x[s] so_lambda: λ2x.t[x] true: True squash: T less_than: a < b sq_exists: x:A [B[x]] rless: x < y nat: sq_stable: SqStable(P) int-rdiv: (a)/k1 has-value: (a)↓ int-to-real: r(n) rsub: y rabs: |x| rminus: -(x) absval: |i| ge: i ≥  subtract: m

Latex:
\mforall{}[x,y:\mBbbR{}].  \mforall{}[k:\mBbbN{}\msupplus{}].    uiff(|x  -  y|  \mleq{}  (r1/r(k));\mforall{}m:\mBbbN{}\msupplus{}.  ((|(x  m)  -  y  m|  *  k)  \mleq{}  ((4  *  k)  +  (2  *  m))))



Date html generated: 2020_05_20-AM-11_05_00
Last ObjectModification: 2019_12_28-PM-08_14_32

Theory : reals


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