Nuprl Lemma : ratmul_wf
∀[a,b:ℤ × ℕ+].  (ratmul(a;b) ∈ {r:ℤ × ℕ+| ratreal(r) = (ratreal(a) * ratreal(b))} )
Proof
Definitions occuring in Statement : 
ratmul: ratmul(a;b)
, 
ratreal: ratreal(r)
, 
req: x = y
, 
rmul: a * b
, 
nat_plus: ℕ+
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
product: x:A × B[x]
, 
int: ℤ
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
ratmul: ratmul(a;b)
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
subtype_rel: A ⊆r B
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
uimplies: b supposing a
, 
guard: {T}
, 
prop: ℙ
Lemmas referenced : 
rat-mul_wf, 
ratreduce_wf, 
subtype_rel_sets_simple, 
nat_plus_wf, 
req_wf, 
ratreal_wf, 
rmul_wf, 
req_inversion, 
req_transitivity, 
istype-int
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
inhabitedIsType, 
lambdaFormation_alt, 
setElimination, 
rename, 
applyEquality, 
productEquality, 
intEquality, 
sqequalRule, 
lambdaEquality_alt, 
independent_isectElimination, 
universeIsType, 
because_Cache, 
equalityIstype, 
equalityTransitivity, 
equalitySymmetry, 
dependent_functionElimination, 
independent_functionElimination, 
productIsType
Latex:
\mforall{}[a,b:\mBbbZ{}  \mtimes{}  \mBbbN{}\msupplus{}].    (ratmul(a;b)  \mmember{}  \{r:\mBbbZ{}  \mtimes{}  \mBbbN{}\msupplus{}|  ratreal(r)  =  (ratreal(a)  *  ratreal(b))\}  )
Date html generated:
2019_10_30-AM-09_22_13
Last ObjectModification:
2019_01_10-PM-01_47_54
Theory : reals
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