Nuprl Lemma : absval_le_zero
∀[i:ℤ]. uiff(|i| ≤ 0;i = 0 ∈ ℤ)
Proof
Definitions occuring in Statement : 
absval: |i|
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
le: A ≤ B
, 
natural_number: $n
, 
int: ℤ
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
less_than: a < b
, 
less_than': less_than'(a;b)
, 
top: Top
, 
true: True
, 
squash: ↓T
, 
not: ¬A
, 
false: False
, 
le: A ≤ B
, 
cand: A c∧ B
, 
guard: {T}
, 
subtype_rel: A ⊆r B
, 
bfalse: ff
, 
exists: ∃x:A. B[x]
, 
or: P ∨ Q
, 
sq_type: SQType(T)
, 
bnot: ¬bb
, 
ifthenelse: if b then t else f fi 
, 
assert: ↑b
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
prop: ℙ
, 
decidable: Dec(P)
, 
subtract: n - m
Lemmas referenced : 
absval_unfold2, 
lt_int_wf, 
eqtt_to_assert, 
assert_of_lt_int, 
istype-top, 
istype-void, 
less_than_transitivity1, 
less_than_irreflexivity, 
istype-le, 
le_weakening, 
le_witness_for_triv, 
int_subtype_base, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
iff_transitivity, 
assert_wf, 
bnot_wf, 
not_wf, 
less_than_wf, 
iff_weakening_uiff, 
assert_of_bnot, 
istype-less_than, 
istype-assert, 
istype-int, 
add_functionality_wrt_le, 
le_reflexive, 
decidable__int_equal, 
istype-false, 
not-equal-2, 
condition-implies-le, 
minus-zero, 
add-zero, 
add-associates, 
minus-add, 
minus-minus, 
minus-one-mul, 
zero-add, 
minus-one-mul-top, 
two-mul, 
add-commutes, 
mul-distributes-right, 
one-mul, 
le-add-cancel, 
not-lt-2
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
sqequalRule, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
natural_numberEquality, 
Error :inhabitedIsType, 
Error :lambdaFormation_alt, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
independent_isectElimination, 
because_Cache, 
lessCases, 
axiomSqEquality, 
Error :isect_memberEquality_alt, 
Error :isectIsTypeImplies, 
independent_pairFormation, 
voidElimination, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
independent_functionElimination, 
dependent_functionElimination, 
Error :equalityIstype, 
applyEquality, 
sqequalBase, 
Error :dependent_pairFormation_alt, 
promote_hyp, 
instantiate, 
cumulativity, 
Error :functionIsType, 
Error :universeIsType, 
independent_pairEquality, 
axiomEquality, 
minusEquality, 
addEquality, 
multiplyEquality, 
intEquality
Latex:
\mforall{}[i:\mBbbZ{}].  uiff(|i|  \mleq{}  0;i  =  0)
Date html generated:
2019_06_20-AM-11_24_30
Last ObjectModification:
2019_02_12-PM-01_59_51
Theory : arithmetic
Home
Index