Open post Jem Lord @jemlord@mathstodon.xyz · 6mo ago Replying to @ncf@types.pl <p>I've just added to my <a href="https://agda.monade.li/EasyParametricity#8031" target="_blank" rel="nofollow noopener">formalisation</a> of <span class="h-card" translate="no"><a href="https://mathstodon.xyz/@jemlord" class="u-url mention" rel="nofollow noopener" target="_blank">@<span>jemlord</span></a></span> 's "<a href="https://hott-uf.github.io/2025/abstracts/HoTTUF_2025_paper_21.pdf" target="_blank" rel="nofollow noopener">Easy Parametricity</a>" a short proof that every function of type (A : U) → A → A is the identity. Such a neat idea!</p> @ncf Yay, thank you! It's cool seeing it come together in a proof assistant.