Wikipedia Talk:Commutative diagram

Request for arrow decorations

I asked over in Talk:Morphism but perhaps here is a better place.
Apparently it's fairly standard in commutative diagrams to use
arrows with a hook ( \hookrightarrow or \252 or ↪) to denote
monomorphisms, double-headed arrows ( \twoheadrightarrow or \240 or
↠) to denote epimorphisms, and double arrows ( \Rightarrow or
=> or ⇒) to denote isomorphisms.  So standard, in fact, that
algebra papers don't even footnote the usage.  It would be nice to
mention this usage and use it in the illustrations, for those of us
who turn to Wikipedia when the paper doesn't make sense.  -Dan Hoey
19:57, 24 May 2007 (UTC)