Meetup summary

2025-01-10 - Generatingfunctionologypracticum - Lazy Sequence (Functional) Edition

  • All the introductory reading on formal power series and computation from the classical methods meetup. on formal power series.
  • Review how painful it was to extract coefficients of a composition of power series even in O(n3)O(n^3) time using classical techniques.
  • M. Douglas McIlroy’s Power series, power serious functional pearl from JFP. This is a wonderful introduction to practical computing with power series, which themselves have direct connections to Analytic Combinatorics through generating functions. It shows how lazy (but automatically memoized) stream types (such as Haskell’s lists) make these computations signifcantly simpler than doing things the “direct” way.
  • Spend some time thinking about your novel knot/novel knot integration for show and tell.

Agenda:

  • Novel Knots show and tell. Try to show up with some unique not that you developed or else some unique way of putting knots together in a working, practical system (or aesthetic display). It’s fine if you later discover that your knot or system was already developed elsewhere; the idea is to get the creative juices flowing and explore how knots work.
    • Check out the novel knots or knot systems/integrations everybody has developed over the past few weeks.
    • Critique and enhance each others’ discoveries.
  • Work through the Power Series, Power Serious paper. The goal is to get through all basic series operations (including series composition; the same stuff we did with classical techniques).
    • I don’t expect to get through “advanced” use cases involving reversion, differentiation/integration, or differential equations. We can do a follow-up session on that if there’s interest.
  • Compare the lazy technique to the classical technique from last time.
    • Ease or difficulty of implementation
    • Understandability (especially for somebody without the requisite background)
    • Runtime and space usage.