Nuprl Lemma : m-open-cover-iff

[X:Type]. ∀[d:metric(X)]. ∀[I:Type]. ∀[A:I ⟶ X ⟶ ℙ].
  (m-open-cover(X;d;I;i,x.A[i;x])
  ⇐⇒ (∀i:I. m-open(X;d;x.A[i;x])) ∧ (∃b:X ⟶ ℕ+. ∃c:X ⟶ I. ∀x,y:X.  ((mdist(d;x;y) ≤ (r1/r(b x)))  A[c x;y])))


Proof




Definitions occuring in Statement :  m-open-cover: m-open-cover(X;d;I;i,x.A[i; x]) m-open: m-open(X;d;x.A[x]) mdist: mdist(d;x;y) metric: metric(X) rdiv: (x/y) rleq: x ≤ y int-to-real: r(n) nat_plus: + uall: [x:A]. B[x] prop: so_apply: x[s1;s2] all: x:A. B[x] exists: x:A. B[x] iff: ⇐⇒ Q implies:  Q and: P ∧ Q apply: a function: x:A ⟶ B[x] natural_number: $n universe: Type
Definitions unfolded in proof :  uall: [x:A]. B[x] iff: ⇐⇒ Q and: P ∧ Q implies:  Q all: x:A. B[x] m-open-cover: m-open-cover(X;d;I;i,x.A[i; x]) member: t ∈ T so_lambda: λ2y.t[x; y] so_apply: x[s1;s2] prop: rev_implies:  Q so_lambda: λ2x.t[x] so_apply: x[s] exists: x:A. B[x] subtype_rel: A ⊆B uimplies: supposing a nat_plus: + guard: {T} m-open: m-open(X;d;x.A[x]) not: ¬A satisfiable_int_formula: satisfiable_int_formula(fmla) false: False pi1: fst(t) rneq: x ≠ y or: P ∨ Q decidable: Dec(P) uiff: uiff(P;Q) rev_uimplies: rev_uimplies(P;Q)

Latex:
\mforall{}[X:Type].  \mforall{}[d:metric(X)].  \mforall{}[I:Type].  \mforall{}[A:I  {}\mrightarrow{}  X  {}\mrightarrow{}  \mBbbP{}].
    (m-open-cover(X;d;I;i,x.A[i;x])
    \mLeftarrow{}{}\mRightarrow{}  (\mforall{}i:I.  m-open(X;d;x.A[i;x]))
            \mwedge{}  (\mexists{}b:X  {}\mrightarrow{}  \mBbbN{}\msupplus{}.  \mexists{}c:X  {}\mrightarrow{}  I.  \mforall{}x,y:X.    ((mdist(d;x;y)  \mleq{}  (r1/r(b  x)))  {}\mRightarrow{}  A[c  x;y])))



Date html generated: 2020_05_20-AM-11_56_12
Last ObjectModification: 2020_01_12-PM-01_13_54

Theory : reals


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