TheHoTTGame/Plan.org
2021-07-16 12:46:01 +01:00

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#+TITLE: Planning The HoTT Game
* Aims of the HoTT Game
** To get mathematicians with no experience in proof verification interested in HoTT and able to use Agda for HoTT
** [?] Work towards showing an interesting result in HoTT
** Try to balance hiding cubical implementations whilst exploiting their advantages
* Barriers
** HOLD Installation of emacs
** TODO Usage of emacs
** TODO General type theoretic foundations
** TODO Cubical type theory
* Format
** [?] Everything done in .agda files
** Partially written code with spaces for participants to fill in + answer files
** Levels set out with mini-bosses like in Nat Num Game, but with an overall boss
** [?] Side quests
** References to Harper lectures and HoTT book
* Content
#+DESCRIPTION: listing topics we have pursued, NO ordering
+ emacs usage
- `data` and `record`
- basic commands (all covered in https://agda.readthedocs.io/en/v2.6.0.1/getting-started/quick-guide.html)
- recommend doom emacs? -> basic doom usage and command differences with nude agda.
- implicit/explicit arguments
- holes and inferred types
- `_+_` and `plus__`
+ type theory basics
- meta (judgemental/definitional) equality vs internal (propositional) equality
- constructing types in universes
- universes
- recursors / pattern matching
- side quest: some natural number exercises as early evidence of being able to 'do maths'?
- different notions of equivalence
a) fibers contractable
b) quasi-inverse
c) zig-zag
- types are infinity groupoids
- positive and negative constructions of Pi/Sigma types
+ HoTT
- basics
a) meta interval, identity type vs path type
b) path type on other types
c) dependent path type PathP vs path over
d) univalence
e) the (non)-issue of J in (Cu)TT
f) isContr, isProp, isSet
- Structures, univalence and transport
a) transporting results between isomorphic structures
- HITs, examples
a) the constructed interval
b) booleans and covers
c) S^n
d)
- Homotopy n-types
a) homotopy levels being closed under type constructions, in particular Set and ETT inside HoTT
* in particular sigma types
* Debriefs
- 2021 July 15; Homotopy n-types + watched (Harper) lecture 15 on Sets being closed under type formations ->- motivates showing in Agda Sets closed under Sigma.
+ Harper does product case, claiming sigma case follows analogously, + attempt proof in Cubical Agda but highly non-obvious how to use that fibers are Sets.
+ difficulty is that PathP not in one fiber, but PathOver is, AND PathOver <-> PathP NON-obvious
+ Easy to generalize situation to n-types being closed under Sigma (7.1.8 in HoTT book), we showed this assuming PathPIsoPath
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