Nuprl Lemma : absval_sym
∀[i:ℤ]. (|i| = |-i| ∈ ℤ)
Proof
Definitions occuring in Statement : 
absval: |i|
, 
uall: ∀[x:A]. B[x]
, 
minus: -n
, 
int: ℤ
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
squash: ↓T
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
nat: ℕ
, 
true: True
, 
uimplies: b supposing a
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
Lemmas referenced : 
equal_wf, 
squash_wf, 
true_wf, 
absval_wf, 
nat_wf, 
absval-minus, 
iff_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
cut, 
applyEquality, 
thin, 
lambdaEquality, 
sqequalHypSubstitution, 
imageElimination, 
introduction, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
universeEquality, 
intEquality, 
setElimination, 
rename, 
sqequalRule, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
independent_isectElimination, 
productElimination, 
independent_functionElimination, 
because_Cache
Latex:
\mforall{}[i:\mBbbZ{}].  (|i|  =  |-i|)
Date html generated:
2017_04_14-AM-07_17_15
Last ObjectModification:
2017_02_27-PM-02_51_55
Theory : arithmetic
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