We show normalisation and decidability of convertibility for a type theory with a hierarchy of universes and a proof irrelevant type of propositions, close to the type system used in the proof assistant Lean. Contrary to previous arguments, the proof does not require explicitly to introduce a notion of neutral and normal forms.

@article{paperbot2205,
  title = {Reduction Free Normalisation for a proof irrelevant type of propositions},
  author = {Thierry Coquand},
  journal = {Logical Methods in Computer Science},
  volume = {Volume 19, Issue 3},
  year = {2023},
  doi = {10.46298/lmcs-19(3:5)2023}
}