Encyclopedia > Talk:Category theory

  Article Content

Talk:Category theory

Must a functor be one-to-one? Can it assign the same object in D to many objects in C, or many objects in D to a single object in C? I can't see that this is ruled out by the requirements on a functor, but maybe I'm just not being smart enough.
-- Stuart Presnell 28/03/2003

A functor can be many-to-one but not one-to-many, so much like a function really. It isn't actually a function because functions are defined on sets and categories are generally 'bigger' than sets. Pcb21 14:06 31 May 2003 (UTC)



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Museums in England

... and Albert Museum Merseyside Customs & Excise National Museum[?] Historic Warships[?], Birkenhead Lady Lever Art Gallery[?] Liverpool Museum[?] Merseyside ...

 
 
 
This page was created in 50.8 ms