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2021 01 26 Meeting

affeldt-aist edited this page Jan 26, 2021 · 1 revision

Participants: Marie, Kazuhiko, Cyril, Reynald

  • About PR https://github.com/math-comp/analysis/pull/205
  • About PR https://github.com/math-comp/analysis/pull/183
    • TODO: use field inverse instead of ring inverse, look at where unitfE is used (normrV -> normfV, mulrV, ...)
    • Shouldn't bounded_funP use a near notation?
    • TODO: try to get rid of exists's in favor of near
      • except when nbhs_ex is used
  • About PR https://github.com/math-comp/analysis/pull/204
    • experiment on defining the same topology on difference vector spaces
    • TODO: sync with zstone1 contributions
  • About Issue https://github.com/math-comp/analysis/issues/301
    • DONE: write a comment to point to PR #283 and close
  • About the next release:
    • release 0.3.6 by the end of the month, possibly with PR #205 and PR #183
  • About measure theory:
    • TODO: spurious pselect before {subset _ <= _}
    • problem with the definition of finite sets of intervals as a ring of sets
      • problem 1: R is not a Type but a realType, the head symbol if Real.sort
      • problem 2: by completion, we'll get a new measurable type on R, itvs_ringOfSets should therefore be a local instance, should go into a module (then close the module and redefine the measure on R as the one given by caratheodory_measurableType)
    • NB: can't replace the Definition itvs_ringOfSets_carrier in Prop by, say, an inductive in Type
    • flow:
      1. l.525, Canonical canonical_outer_measure OuterMeasure.OuterMeasure should not appear, rename the constructor OuterMeasure as Axioms or Build (l.716, measure.v)
      2. l.265, Definition caratheodory_measurableType builds a measure from an outer measure l.292, HB.instance Definition instance is global on measurables mu (not on R)
      3. in section Hahn, Let M : measurableType := caratheodory_measurableType mstar. should become Let M : measurableType := [measurableType of measurables (mu_ext mu)]. but since we do not have yet the notation [measurableType of ...] (and also because mu_ext mu is not of the right type(?)) it will become Let M : measurableType := [the measurableType of measurables [outer_measure of mu_ext mu]]. NB: [measurableType of ...] available as a feature of hb.1.0.0 Still, we should strive for Let M : measurableType := [measurableType of {measurables (mu_ext mu)}]. for documentation purposes l.734, Let Hahn_mu [outer_measure of mstar] should work
      4. HB.instance Definition itvs_ringOfSets in a module (an alternative could have been to introduce an alias, say, itvs_measurables_of_R but anyway this is supposed to be internal) length might require typing information
    • memo: Definition gen_measurable is a copy of U on which we have a structure of measurableType
    • memo: l.313, Canonical caratheodory_measure, might become a problem
  • TODO: create an issue about floor and ceil to remember to replace the code when the hierarchy in MathComp is refined
  • About inf sums:
    • PYS reports progress but still needs a few weeks