Nuprl Lemma : olympiad-problem-six
∀k:ℤ. ∀a,b:ℕ.  ((((a * a) + (b * b)) = (k * ((a * b) + 1)) ∈ ℤ) 
⇒ (∃n:ℤ. (k = (n * n) ∈ ℤ)))
Proof
Definitions occuring in Statement : 
nat: ℕ
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
implies: P 
⇒ Q
, 
multiply: n * m
, 
add: n + m
, 
natural_number: $n
, 
int: ℤ
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
le: A ≤ B
, 
uimplies: b supposing a
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
top: Top
, 
prop: ℙ
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
subtype_rel: A ⊆r B
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
guard: {T}
, 
sq_type: SQType(T)
, 
nat: ℕ
, 
ge: i ≥ j 
, 
nat_plus: ℕ+
Lemmas referenced : 
int_seg_properties, 
full-omega-unsat, 
intformand_wf, 
intformless_wf, 
itermVar_wf, 
itermConstant_wf, 
intformle_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_le_lemma, 
int_formula_prop_wf, 
int_seg_wf, 
decidable__equal_int, 
subtract_wf, 
subtype_base_sq, 
set_subtype_base, 
int_subtype_base, 
intformnot_wf, 
intformeq_wf, 
itermSubtract_wf, 
int_formula_prop_not_lemma, 
int_formula_prop_eq_lemma, 
int_term_value_subtract_lemma, 
decidable__le, 
decidable__lt, 
istype-le, 
istype-less_than, 
subtype_rel_self, 
nat_properties, 
itermAdd_wf, 
itermMultiply_wf, 
int_term_value_add_lemma, 
int_term_value_mul_lemma, 
le_wf, 
nat_wf, 
equal-wf-base, 
lelt_wf, 
primrec-wf2, 
istype-nat, 
mul_bounds_1a, 
mul_cancel_in_le, 
add_nat_plus, 
multiply_nat_wf, 
nat_plus_properties, 
mul_preserves_le, 
square_non_neg, 
mul_cancel_in_lt
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :lambdaFormation_alt, 
cut, 
thin, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
setElimination, 
rename, 
productElimination, 
hypothesis, 
hypothesisEquality, 
natural_numberEquality, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
Error :dependent_pairFormation_alt, 
Error :lambdaEquality_alt, 
int_eqEquality, 
dependent_functionElimination, 
Error :isect_memberEquality_alt, 
voidElimination, 
sqequalRule, 
independent_pairFormation, 
Error :universeIsType, 
unionElimination, 
applyEquality, 
instantiate, 
because_Cache, 
equalityTransitivity, 
equalitySymmetry, 
applyLambdaEquality, 
Error :dependent_set_memberEquality_alt, 
Error :productIsType, 
hypothesis_subsumption, 
cumulativity, 
intEquality, 
Error :equalityIstype, 
baseApply, 
closedConclusion, 
baseClosed, 
Error :inhabitedIsType, 
sqequalBase, 
Error :functionIsType, 
functionEquality, 
productEquality, 
Error :setIsType, 
addEquality, 
multiplyEquality
Latex:
\mforall{}k:\mBbbZ{}.  \mforall{}a,b:\mBbbN{}.    ((((a  *  a)  +  (b  *  b))  =  (k  *  ((a  *  b)  +  1)))  {}\mRightarrow{}  (\mexists{}n:\mBbbZ{}.  (k  =  (n  *  n))))
Date html generated:
2019_06_20-PM-02_43_07
Last ObjectModification:
2019_03_10-PM-02_32_31
Theory : num_thy_1
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