Nuprl Lemma : fractions-rleq

∀a,b,c,d:ℝ.  ((r0 < c) ⇒ (r0 < d) ⇒ ((a/c) ≤ (b/d) ⇐⇒ (a * d) ≤ (b * c)))


Proof




Definitions occuring in Statement :  rdiv: (x/y),  rleq: x ≤ y,  rless: x < y,  rmul: a * b,  int-to-real: r(n),  real: ℝ,  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  implies: P ⇒ Q,  natural_number: $n
Definitions unfolded in proof :  all: ∀x:A. B[x],  implies: P ⇒ Q,  iff: P ⇐⇒ Q,  and: P ∧ Q,  member: t ∈ T,  prop: ℙ,  uall: ∀[x:A]. B[x],  uimplies: b supposing a,  rneq: x ≠ y,  guard: {T},  or: P ∨ Q,  rev_implies: P ⇐ Q,  uiff: uiff(P;Q),  rdiv: (x/y),  req_int_terms: t1 ≡ t2,  false: False,  not: ¬A,  top: Top,  rev_uimplies: rev_uimplies(P;Q)
Lemmas referenced :  rleq_wf,  rdiv_wf,  rless_wf,  int-to-real_wf,  rmul_wf,  real_wf,  rmul_preserves_rleq2,  rleq_weakening_rless,  rinv_wf2,  itermSubtract_wf,  itermMultiply_wf,  itermVar_wf,  req-iff-rsub-is-0,  rmul-one,  itermConstant_wf,  rleq_functionality,  req_transitivity,  rmul_functionality,  req_weakening,  rmul-rinv,  real_polynomial_null,  real_term_value_sub_lemma,  real_term_value_mul_lemma,  real_term_value_var_lemma,  real_term_value_const_lemma,  rmul_preserves_rleq
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  independent_pairFormation,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  independent_isectElimination,  sqequalRule,  hypothesis,  inrFormation,  natural_numberEquality,  because_Cache,  independent_functionElimination,  productElimination,  dependent_functionElimination,  approximateComputation,  lambdaEquality,  int_eqEquality,  intEquality,  isect_memberEquality,  voidElimination,  voidEquality

Latex:
\mforall{}a,b,c,d:\mBbbR{}.    ((r0  <  c)  {}\mRightarrow{}  (r0  <  d)  {}\mRightarrow{}  ((a/c)  \mleq{}  (b/d)  \mLeftarrow{}{}\mRightarrow{}  (a  *  d)  \mleq{}  (b  *  c)))



Date html generated: 2017_10_03-AM-08_39_07
Last ObjectModification: 2017_09_07-PM-06_37_36

Theory : reals


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