Nuprl Lemma : rabs-rminus
∀[x:ℝ]. (|-(x)| = |x| ∈ ℝ)
Proof
Definitions occuring in Statement : 
rabs: |x|, 
rminus: -(x), 
real: ℝ, 
uall: ∀[x:A]. B[x], 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
real: ℝ, 
member: t ∈ T, 
nat_plus: ℕ+, 
less_than: a < b, 
squash: ↓T, 
less_than': less_than'(a;b), 
true: True, 
and: P ∧ Q, 
prop: ℙ, 
implies: P ⇒ Q, 
rev_implies: P ⇐ Q, 
iff: P ⇐⇒ Q, 
guard: {T}, 
uimplies: b supposing a, 
nat: ℕ, 
subtype_rel: A ⊆r B, 
rminus: -(x), 
rabs: |x|
Lemmas referenced : 
real-regular, 
rabs_wf, 
rminus_wf, 
less_than_wf, 
regular-int-seq_wf, 
iff_weakening_equal, 
absval-minus, 
true_wf, 
squash_wf, 
equal_wf, 
nat_wf, 
absval_wf, 
nat_plus_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
cut, 
dependent_set_memberEquality, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
natural_numberEquality, 
sqequalRule, 
independent_pairFormation, 
imageMemberEquality, 
baseClosed, 
because_Cache, 
independent_functionElimination, 
productElimination, 
independent_isectElimination, 
universeEquality, 
equalitySymmetry, 
equalityTransitivity, 
imageElimination, 
lambdaEquality, 
rename, 
setElimination, 
applyEquality, 
intEquality, 
functionExtensionality
Latex:
\mforall{}[x:\mBbbR{}].  (|-(x)|  =  |x|)
Date html generated:
2017_10_03-AM-08_22_57
Last ObjectModification:
2017_09_20-PM-05_36_35
Theory : reals
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