Nuprl Lemma : qmul_reverses_qless
∀[a,b,c:ℚ].  uiff(a < b;c * b < c * a) supposing c < 0
Proof
Definitions occuring in Statement : 
qless: r < s
, 
qmul: r * s
, 
rationals: ℚ
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
natural_number: $n
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
rev_uimplies: rev_uimplies(P;Q)
, 
uimplies: b supposing a
, 
true: True
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
squash: ↓T
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
qmul_com, 
qadd_ac_1_q, 
qmul_comm_qrng, 
qmul_over_minus_qrng, 
qmul_preserves_qless, 
iff_weakening_equal, 
mon_ident_q, 
qinverse_q, 
qadd_comm_q, 
true_wf, 
squash_wf, 
qless_witness, 
rationals_wf, 
int-subtype-rationals, 
qless_wf, 
qadd_wf, 
qmul_wf, 
qadd_preserves_qless
Rules used in proof : 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isectElimination, 
thin, 
because_Cache, 
minusEquality, 
natural_numberEquality, 
hypothesis, 
applyEquality, 
sqequalRule, 
hypothesisEquality, 
productElimination, 
independent_isectElimination, 
isect_memberFormation, 
introduction, 
independent_pairEquality, 
isect_memberEquality, 
independent_functionElimination, 
equalityTransitivity, 
equalitySymmetry, 
lambdaEquality, 
imageElimination, 
imageMemberEquality, 
baseClosed, 
universeEquality, 
independent_pairFormation
Latex:
\mforall{}[a,b,c:\mBbbQ{}].    uiff(a  <  b;c  *  b  <  c  *  a)  supposing  c  <  0
Date html generated:
2016_05_15-PM-10_59_41
Last ObjectModification:
2016_01_16-PM-09_31_54
Theory : rationals
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