Nuprl Lemma : ab-divides-a^2+b^2+1
∀a,b:ℤ.
  ((a * b) | (((a * a) + (b * b)) + 1)
  ⇐⇒ ∃n:ℕ. ((<|a|, |b|> = vexample(n;1;1) ∈ (ℤ × ℤ)) ∨ (<|b|, |a|> = vexample(n;1;1) ∈ (ℤ × ℤ))))
Proof
Definitions occuring in Statement : 
vexample: vexample(n;a;b), 
divides: b | a, 
absval: |i|, 
nat: ℕ, 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
iff: P ⇐⇒ Q, 
or: P ∨ Q, 
pair: <a, b>, 
product: x:A × B[x], 
multiply: n * m, 
add: n + m, 
natural_number: $n, 
int: ℤ, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
implies: P ⇒ Q, 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
subtype_rel: A ⊆r B, 
prop: ℙ, 
rev_implies: P ⇐ Q, 
exists: ∃x:A. B[x], 
or: P ∨ Q, 
nat: ℕ, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
uimplies: b supposing a, 
squash: ↓T, 
guard: {T}, 
true: True, 
divides: b | a, 
decidable: Dec(P), 
le: A ≤ B, 
not: ¬A, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
false: False, 
top: Top, 
uiff: uiff(P;Q), 
ge: i ≥ j , 
pi2: snd(t), 
pi1: fst(t)
Lemmas referenced : 
divides_wf, 
absval_wf, 
istype-nat, 
int_subtype_base, 
set_subtype_base, 
le_wf, 
istype-int, 
absval-divides, 
absval_mul, 
iff_weakening_equal, 
squash_wf, 
true_wf, 
add_functionality_wrt_eq, 
absval_squared, 
subtype_rel_self, 
Vieta-jumping-example2-corollary, 
decidable__le, 
decidable__equal_int, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformeq_wf, 
itermAdd_wf, 
itermMultiply_wf, 
itermVar_wf, 
itermConstant_wf, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_not_lemma, 
int_formula_prop_eq_lemma, 
int_term_value_add_lemma, 
int_term_value_mul_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_wf, 
add-is-int-iff, 
multiply-is-int-iff, 
intformle_wf, 
int_formula_prop_le_lemma, 
false_wf, 
vexample_wf, 
nat_properties, 
istype-le, 
pi2_wf, 
pi1_wf, 
nat_wf, 
equal_wf, 
istype-universe
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :lambdaFormation_alt, 
cut, 
thin, 
independent_pairFormation, 
Error :universeIsType, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
multiplyEquality, 
hypothesisEquality, 
hypothesis, 
applyEquality, 
because_Cache, 
sqequalRule, 
addEquality, 
natural_numberEquality, 
Error :productIsType, 
Error :unionIsType, 
Error :equalityIstype, 
baseApply, 
closedConclusion, 
baseClosed, 
intEquality, 
Error :lambdaEquality_alt, 
Error :inhabitedIsType, 
independent_isectElimination, 
sqequalBase, 
equalitySymmetry, 
productElimination, 
independent_functionElimination, 
promote_hyp, 
dependent_functionElimination, 
setElimination, 
rename, 
equalityTransitivity, 
imageElimination, 
imageMemberEquality, 
instantiate, 
universeEquality, 
unionElimination, 
approximateComputation, 
Error :dependent_pairFormation_alt, 
int_eqEquality, 
Error :isect_memberEquality_alt, 
voidElimination, 
Error :inlFormation_alt, 
pointwiseFunctionality, 
Error :inrFormation_alt, 
Error :dependent_set_memberEquality_alt, 
applyLambdaEquality
Latex:
\mforall{}a,b:\mBbbZ{}.
    ((a  *  b)  |  (((a  *  a)  +  (b  *  b))  +  1)
    \mLeftarrow{}{}\mRightarrow{}  \mexists{}n:\mBbbN{}.  ((<|a|,  |b|>  =  vexample(n;1;1))  \mvee{}  (<|b|,  |a|>  =  vexample(n;1;1))))
Date html generated:
2019_06_20-PM-02_43_55
Last ObjectModification:
2019_03_11-PM-06_33_37
Theory : num_thy_1
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