tag:dreamwidth.org,2016-12-25:2614584 timelets timelets 2017-12-23T18:26:08Z tag:dreamwidth.org,2016-12-25:2614584:743203 2017-12-23T18:24:32Z 2017-12-23T18:26:08Z public 0 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