I often call them "test objects" in talking with students (by analogy with "test particles" in General Relativity). I don't think I have ever done it in print. But I did use "T" as the typical name of such an object in my book. I am curious to know what others think. best, Colin ----- Original Message ----- From: categories@mta.ca Date: Tuesday, January 20, 2009 11:01 am Subject: categories: terminology in definitions of limits To: categories@mta.ca
Folk,
Each definition of a limit which I've seen contains something I would describe as a "probe object" or "test object". The definition of map object in L&S page 313 for example, has X with a criterion asserted for every object X in the category.
Is there any sense in my terminology?
Thanks, ... Peter E.