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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