Nuprl Lemma : int-with-rational-square-root
∀n:ℤ. ∀q:ℚ.  (((q * q) = n ∈ ℚ) 
⇒ (∃m:ℤ. ((m * m) = n ∈ ℤ)))
Proof
Definitions occuring in Statement : 
qmul: r * s
, 
rationals: ℚ
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
implies: P 
⇒ Q
, 
multiply: n * m
, 
int: ℤ
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
subtype_rel: A ⊆r B
, 
squash: ↓T
, 
prop: ℙ
, 
true: True
, 
uimplies: b supposing a
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
pi1: fst(t)
, 
pi2: snd(t)
, 
mk-rational: mk-rational(a;b)
, 
rationals: ℚ
, 
quotient: x,y:A//B[x; y]
, 
nat_plus: ℕ+
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
exists: ∃x:A. B[x]
, 
cand: A c∧ B
, 
coprime: CoPrime(a,b)
, 
gcd_p: GCD(a;b;y)
, 
sq_type: SQType(T)
, 
not: ¬A
, 
false: False
, 
or: P ∨ Q
, 
divides: b | a
, 
decidable: Dec(P)
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
prime: prime(a)
, 
assoced: a ~ b
, 
int_upper: {i...}
, 
label: ...$L... t
, 
sq_exists: ∃x:A [B[x]]
, 
cons: [a / b]
, 
mul-list: Π(ns) 
, 
reduce: reduce(f;k;as)
, 
list_ind: list_ind
Lemmas referenced : 
qmul_wf, 
int-subtype-rationals, 
rationals_wf, 
istype-int, 
equals-qrep, 
qrep-coprime, 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
subtype_rel_self, 
iff_weakening_equal, 
qrep_wf, 
b-union_wf, 
int_nzero_wf, 
bool_wf, 
qeq_wf2, 
mk-rational_wf, 
nat_plus_inc_int_nzero, 
btrue_wf, 
set_subtype_base, 
less_than_wf, 
int_subtype_base, 
qeq-elim, 
qmul-elim, 
eqtt_to_assert, 
assert_of_eq_int, 
coprime_wf, 
one_divs_any, 
divides_wf, 
gcd_is_gcd, 
absval_ifthenelse, 
gcd_wf, 
lt_int_wf, 
subtype_base_sq, 
assert_wf, 
bnot_wf, 
not_wf, 
istype-less_than, 
istype-assert, 
istype-void, 
divides_invar_2, 
bool_cases, 
bool_subtype_base, 
assert_of_lt_int, 
eqff_to_assert, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bnot, 
prime_wf, 
prime_divs_prod, 
nat_plus_properties, 
decidable__equal_int, 
full-omega-unsat, 
intformnot_wf, 
intformeq_wf, 
itermMultiply_wf, 
itermVar_wf, 
int_formula_prop_not_lemma, 
int_formula_prop_eq_lemma, 
int_term_value_mul_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
nat_plus_wf, 
decidable__equal_nat_plus, 
decidable__lt, 
intformless_wf, 
itermConstant_wf, 
int_formula_prop_less_lemma, 
int_term_value_constant_lemma, 
prime-factors, 
decidable__le, 
intformand_wf, 
intformle_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_le_lemma, 
istype-le, 
set_wf, 
int_upper_wf, 
list-cases, 
product_subtype_list, 
mul_list_nil_lemma, 
mul-list_wf, 
subtype_rel_list, 
istype-int_upper, 
le_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
equalityIstype, 
inhabitedIsType, 
hypothesisEquality, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesis, 
applyEquality, 
sqequalRule, 
universeIsType, 
lambdaEquality_alt, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
instantiate, 
universeEquality, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
because_Cache, 
independent_isectElimination, 
productElimination, 
independent_functionElimination, 
dependent_functionElimination, 
pertypeElimination, 
promote_hyp, 
productIsType, 
intEquality, 
productEquality, 
sqequalBase, 
baseApply, 
closedConclusion, 
isintReduceTrue, 
multiplyEquality, 
setElimination, 
rename, 
dependent_pairFormation_alt, 
independent_pairFormation, 
cumulativity, 
functionIsType, 
unionElimination, 
voidElimination, 
approximateComputation, 
int_eqEquality, 
Error :memTop, 
dependent_set_memberEquality_alt, 
hypothesis_subsumption, 
setEquality, 
setIsType
Latex:
\mforall{}n:\mBbbZ{}.  \mforall{}q:\mBbbQ{}.    (((q  *  q)  =  n)  {}\mRightarrow{}  (\mexists{}m:\mBbbZ{}.  ((m  *  m)  =  n)))
Date html generated:
2020_05_20-AM-09_31_06
Last ObjectModification:
2020_01_01-AM-11_44_42
Theory : rationals
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