A diagram of Delta-maps.
<a href="//commons.wikimedia.org/w/index.php?title=User:Homo_morphisms&amp;action=edit&amp;redlink=1" class="new" title="User:Homo morphisms (page does not exist)">Homo morphisms</a>
2022-04-20
<span class="int-own-work" lang="en">Own work</span>