Nuprl Lemma : combine-rless

a,b,c,d:ℝ.  ((a < b)  (c < d)  (((b c) (a d)) < ((b d) (a c))))


Proof




Definitions occuring in Statement :  rless: x < y rmul: b radd: b real: all: x:A. B[x] implies:  Q
Definitions unfolded in proof :  all: x:A. B[x] implies:  Q member: t ∈ T uall: [x:A]. B[x] iff: ⇐⇒ Q and: P ∧ Q rev_implies:  Q or: P ∨ Q cand: c∧ B uimplies: supposing a prop: uiff: uiff(P;Q) req_int_terms: t1 ≡ t2 false: False not: ¬A top: Top
Lemmas referenced :  rmul-is-positive rsub_wf rless-implies-rless int-to-real_wf rless_wf radd_wf rmul_wf real_wf itermSubtract_wf itermVar_wf itermConstant_wf req-iff-rsub-is-0 itermMultiply_wf itermAdd_wf real_polynomial_null istype-int real_term_value_sub_lemma istype-void real_term_value_var_lemma real_term_value_const_lemma real_term_value_mul_lemma real_term_value_add_lemma
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity lambdaFormation_alt cut introduction extract_by_obid sqequalHypSubstitution dependent_functionElimination thin isectElimination hypothesisEquality hypothesis productElimination independent_functionElimination inlFormation_alt natural_numberEquality because_Cache independent_isectElimination independent_pairFormation sqequalRule productIsType universeIsType inhabitedIsType approximateComputation lambdaEquality_alt int_eqEquality isect_memberEquality_alt voidElimination

Latex:
\mforall{}a,b,c,d:\mBbbR{}.    ((a  <  b)  {}\mRightarrow{}  (c  <  d)  {}\mRightarrow{}  (((b  *  c)  +  (a  *  d))  <  ((b  *  d)  +  (a  *  c))))



Date html generated: 2019_10_29-AM-10_05_29
Last ObjectModification: 2019_04_09-AM-10_58_54

Theory : reals


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