https://timelets.dreamwidth.org/ timelets - Dreamwidth Studios Sat, 23 Dec 2017 18:24:32 GMT LiveJournal / Dreamwidth Studios timelets personal https://v2.dreamwidth.org/10862491/2614584 https://timelets.dreamwidth.org/ 100 86 https://timelets.dreamwidth.org/743203.html Sat, 23 Dec 2017 18:24:32 GMT https://timelets.dreamwidth.org/743203.html I keep forgetting that external diagrams lose some info to elevate the level of abstraction. The lost info is partially (?) recovered by the introduction of the concepts of injective, surjective, bijective, etc.<br /><br /><img src="https://timelets.dreamwidth.org/file/58861.png" width="600/"><br /><br />-- figure from Lawvere and Rosenbrugh, 2003.<br /><br /><img src="https://www.dreamwidth.org/tools/commentcount?user=timelets&ditemid=743203" width="30" height="12" alt="comment count unavailable" style="vertical-align: middle;"/> comments https://timelets.dreamwidth.org/743203.html set category public 0