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: b int-to-real: r(n) real: all: x:A. B[x] iff: ⇐⇒ Q implies:  Q natural_number: $n
Definitions unfolded in proof :  all: x:A. B[x] implies:  Q iff: ⇐⇒ Q and: P ∧ Q member: t ∈ T prop: uall: [x:A]. B[x] uimplies: supposing a rneq: x ≠ y guard: {T} or: P ∨ Q rev_implies:  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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