Cofree Comonads and their Uses
summary
Defines cofree comonads as a product type that annotates trees and streams and shows concrete encodings: stream = cofree over Identity, prefix list = cofree over Maybe. Implements a finite‑state machine for a blind auction as a cofree comonad, computes running medians via the store comonad for image blurs, and derives Merkle‑tree verification and a blockchain model where extend verifies the whole chain. Uses Haskell code, cofree comonad transformers, and practical type‑constraint tricks; slides linked in the description.
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chapters (12)
- 0:00Start
- 9:06Suffix Trees
- 9:53Merkle Trees
- 11:01Store
- 11:55Image Regions
- 14:58Cofree in Disguise
- 16:15Annotating DSLS
- 19:00Blind Auction Moore Machine
- 20:53Blind Auction Machine
- 23:46Comonad Transformers
- 25:27Cofree Comonad Transformer
- 26:15Blockchain as a Comonad
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