Nuprl Lemma : rsub-int-fractions

[a,b:ℤ]. ∀[c,d:ℕ+].  (((r(a)/r(c)) (r(b)/r(d))) (r((a d) c)/r(c d)))


Proof




Definitions occuring in Statement :  rdiv: (x/y) rsub: y req: y int-to-real: r(n) nat_plus: + uall: [x:A]. B[x] multiply: m subtract: m int:
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T nat_plus: + uimplies: supposing a rneq: x ≠ y guard: {T} or: P ∨ Q all: x:A. B[x] iff: ⇐⇒ Q and: P ∧ Q rev_implies:  Q implies:  Q decidable: Dec(P) not: ¬A satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] false: False prop: true: True subtract: m squash: T subtype_rel: A ⊆B rsub: y uiff: uiff(P;Q) rev_uimplies: rev_uimplies(P;Q)

Latex:
\mforall{}[a,b:\mBbbZ{}].  \mforall{}[c,d:\mBbbN{}\msupplus{}].    (((r(a)/r(c))  -  (r(b)/r(d)))  =  (r((a  *  d)  -  b  *  c)/r(c  *  d)))



Date html generated: 2020_05_20-AM-11_00_43
Last ObjectModification: 2020_01_03-AM-11_17_22

Theory : reals


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