Nuprl Lemma : better-gcd-gcd
∀[y,x:ℤ].  (better-gcd(x;y) ~ gcd(x;y))
Proof
Definitions occuring in Statement : 
better-gcd: better-gcd(a;b)
, 
gcd: gcd(a;b)
, 
uall: ∀[x:A]. B[x]
, 
int: ℤ
, 
sqequal: s ~ t
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
sq_type: SQType(T)
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
guard: {T}
, 
nat: ℕ
, 
false: False
, 
ge: i ≥ j 
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
not: ¬A
, 
rev_implies: P 
⇐ Q
, 
uiff: uiff(P;Q)
, 
subtract: n - m
, 
top: Top
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
true: True
, 
has-value: (a)↓
, 
nequal: a ≠ b ∈ T 
, 
gcd: gcd(a;b)
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
better-gcd: better-gcd(a;b)
, 
int_nzero: ℤ-o
, 
squash: ↓T
Lemmas referenced : 
subtype_base_sq, 
int_subtype_base, 
nat_properties, 
less_than_transitivity1, 
less_than_irreflexivity, 
ge_wf, 
less_than_wf, 
absval_wf, 
decidable__le, 
subtract_wf, 
istype-false, 
not-ge-2, 
less-iff-le, 
condition-implies-le, 
minus-one-mul, 
zero-add, 
minus-one-mul-top, 
istype-void, 
minus-add, 
minus-minus, 
add-associates, 
add-swap, 
add-commutes, 
add_functionality_wrt_le, 
add-zero, 
le-add-cancel, 
nat_wf, 
absval-non-neg, 
eq_int_wf, 
equal-wf-base, 
bool_wf, 
assert_wf, 
bnot_wf, 
not_wf, 
value-type-has-value, 
int-value-type, 
uiff_transitivity, 
eqtt_to_assert, 
assert_of_eq_int, 
iff_transitivity, 
iff_weakening_uiff, 
eqff_to_assert, 
assert_of_bnot, 
rem_bounds_z, 
nequal_wf, 
equal_wf, 
squash_wf, 
true_wf, 
decidable__lt, 
not-lt-2, 
gcd_wf, 
subtype_rel_self, 
iff_weakening_equal, 
zero-mul, 
add-mul-special, 
false_wf, 
le_wf, 
not-le-2
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
thin, 
instantiate, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
cumulativity, 
intEquality, 
independent_isectElimination, 
hypothesis, 
dependent_functionElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
axiomSqEquality, 
Error :inhabitedIsType, 
hypothesisEquality, 
sqequalRule, 
Error :isect_memberEquality_alt, 
Error :universeIsType, 
Error :lambdaFormation_alt, 
setElimination, 
rename, 
intWeakElimination, 
natural_numberEquality, 
voidElimination, 
Error :lambdaEquality_alt, 
axiomEquality, 
applyEquality, 
because_Cache, 
unionElimination, 
independent_pairFormation, 
productElimination, 
addEquality, 
minusEquality, 
baseApply, 
closedConclusion, 
baseClosed, 
Error :equalityIsType3, 
callbyvalueReduce, 
remainderEquality, 
equalityElimination, 
Error :equalityIsType1, 
Error :dependent_set_memberEquality_alt, 
imageElimination, 
universeEquality, 
imageMemberEquality, 
multiplyEquality, 
voidEquality, 
isect_memberEquality, 
lambdaEquality, 
lambdaFormation, 
dependent_set_memberEquality
Latex:
\mforall{}[y,x:\mBbbZ{}].    (better-gcd(x;y)  \msim{}  gcd(x;y))
Date html generated:
2019_06_20-AM-11_25_31
Last ObjectModification:
2018_09_28-AM-11_57_29
Theory : arithmetic
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