UniMath / agda-unimath

The agda-unimath library
https://unimath.github.io/agda-unimath/
MIT License
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Postulate components of coherent two-sided inverses for function extensionality and univalence #1119

Closed fredrik-bakke closed 5 months ago

fredrik-bakke commented 5 months ago

Changes the postulates for funext and univalence such that there is judgmentally only one converse map to htpy-eq and equiv-eq. The main benefit, however, is that now eq-htpy and eq-equiv will appear with their own names in Agda interactive mode, rather than as pr1 (pr1 (funext ... ...)) and pr1 (pr1 (univalence ... ...)).

I leave it for potential future work to prove is-retraction-eq-(equiv|htpy)' and coh-eq-(equiv|htpy)' rather than postulate them, if we want this. Note that we could get away with even fewer postulates if we really wanted to (see TypeTopology/UF.Lower-FunExt).