Nuprl Lemma : rabs-rminus

[x:ℝ]. (|-(x)| |x| ∈ ℝ)


Proof




Definitions occuring in Statement :  rabs: |x| rminus: -(x) real: uall: [x:A]. B[x] equal: t ∈ T
Definitions unfolded in proof :  uall: [x:A]. B[x] real: member: t ∈ T nat_plus: + less_than: a < b squash: T less_than': less_than'(a;b) true: True and: P ∧ Q prop: implies:  Q rev_implies:  Q iff: ⇐⇒ Q guard: {T} uimplies: supposing a nat: subtype_rel: A ⊆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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