Nuprl Lemma : gcd_exists
∀a,b:ℤ.  ∃y:ℤ. GCD(a;b;y)
Proof
Definitions occuring in Statement : 
gcd_p: GCD(a;b;y)
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
int: ℤ
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
nat: ℕ
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
exists: ∃x:A. B[x]
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
uimplies: b supposing a
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
false: False
, 
top: Top
Lemmas referenced : 
decidable__le, 
istype-int, 
gcd_exists_n, 
le_wf, 
gcd_p_neg_arg_2, 
gcd_p_wf, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermMinus_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_minus_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
natural_numberEquality, 
hypothesisEquality, 
hypothesis, 
unionElimination, 
Error :inhabitedIsType, 
Error :dependent_set_memberEquality_alt, 
Error :universeIsType, 
isectElimination, 
productElimination, 
Error :dependent_pairFormation_alt, 
independent_functionElimination, 
because_Cache, 
minusEquality, 
independent_isectElimination, 
approximateComputation, 
Error :lambdaEquality_alt, 
int_eqEquality, 
Error :isect_memberEquality_alt, 
voidElimination, 
sqequalRule, 
independent_pairFormation
Latex:
\mforall{}a,b:\mBbbZ{}.    \mexists{}y:\mBbbZ{}.  GCD(a;b;y)
Date html generated:
2019_06_20-PM-02_22_17
Last ObjectModification:
2018_10_03-AM-00_12_24
Theory : num_thy_1
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