Mechanizing Synthetic Tait Computability in Istari
summary
Mechanization of Synthetic Tait Computability is formalized in the Istari extensional type theory with equality reflection, producing a reusable library of modalities, extension types, strict glue types and two complete case studies: a canonicity model for dependent type theory with pi and booleans (large elimination) and a Kripke canonicity model for the cost‑aware logical framework. Core STC constructions translate virtually verbatim, avoiding transport hell; typical tactic proofs run ~100 lines for booleans, ~200–300 for pis and ~1000 for large elimination, and all results are machine‑checked with artifacts available.
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chapters (15)
- 0:00Synthetic Tait computability intro
- 1:03Canonicity theorem example
- 3:30Categorical proof interpretation
- 5:16Synthetic Tait computability explained
- 7:02Synthetic approach details
- 9:36Transport reasoning in proofs
- 10:59Extism proof assistant intro
- 13:07Type checking in Extism
- 14:11Phase distinction mechanized
- 15:37Canonicity models overview
- 16:42Comparison with intentional provers
- 18:11Conclusion and future work
- 19:19Q&A: Reproducing in other provers
- 20:50Q&A: Nuprl historical comparison
- 21:32Q&A: Extism user experience
