Nuprl Lemma : mul_preserves_le2
∀[a,c:ℕ]. ∀[b,d:ℤ].  ((a * c) ≤ (b * d)) supposing ((a ≤ b) and (c ≤ d))
Proof
Definitions occuring in Statement : 
nat: ℕ
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
le: A ≤ B
, 
multiply: n * m
, 
int: ℤ
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
nat: ℕ
, 
and: P ∧ Q
, 
le: A ≤ B
, 
cand: A c∧ B
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
sq_stable: SqStable(P)
, 
guard: {T}
, 
squash: ↓T
, 
top: Top
Lemmas referenced : 
mul_preserves_le, 
sq_stable_from_decidable, 
le_wf, 
decidable__le, 
le_transitivity, 
istype-le, 
le_witness_for_triv, 
istype-int, 
istype-nat, 
istype-void, 
mul-commutes
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
because_Cache, 
hypothesisEquality, 
independent_isectElimination, 
hypothesis, 
Error :dependent_set_memberEquality_alt, 
setElimination, 
rename, 
independent_pairFormation, 
productElimination, 
natural_numberEquality, 
independent_functionElimination, 
dependent_functionElimination, 
sqequalRule, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
Error :isect_memberEquality_alt, 
Error :isectIsTypeImplies, 
Error :inhabitedIsType, 
voidElimination
Latex:
\mforall{}[a,c:\mBbbN{}].  \mforall{}[b,d:\mBbbZ{}].    ((a  *  c)  \mleq{}  (b  *  d))  supposing  ((a  \mleq{}  b)  and  (c  \mleq{}  d))
Date html generated:
2019_06_20-AM-11_23_20
Last ObjectModification:
2019_02_08-PM-01_26_03
Theory : arithmetic
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