Macros for image, coimage, and cokernel

Asked Dec 03 '14 at 13:04

Active Dec 03 '14 at 13:09

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I work in LyX. There's a default macro for the kernel: \ker which has nice spacing if I put something after it, compared to \text{ker}. I'd like to have macros with the same nice spacing for the image, coimage, and cokernel, respectively im, coim, coker.

asked Dec 03 '14 at 13:04

Exterior

Related: http://tex.stackexchange.com/questions/67506/newcommand-vs-declaremathoperator – egreg Dec 03 '14 at 13:08
And please avoid co<...> terms if it is possible to mention it otherwise. It's pretty much a jargon for let say matrices and many other linear operators. – percusse Dec 03 '14 at 13:09
@percusse, I don't understand. I want these macros for notes on category theory. – Exterior Dec 03 '14 at 13:10
@Exterior Nevermind then :) – percusse Dec 03 '14 at 13:11
@percusse why do you say avoid "co" expressions? – Gonzalo Medina Dec 03 '14 at 13:11
@GonzaloMedina Because most of the time with exceptions such as category theory, it is possible to just say ker(A') etc. depending on the operator. co<...> adds yet another layer of difficulty on the nonmathematician reader though the underlying idea remains unchanged. – percusse Dec 03 '14 at 13:13
@percusse who cares about nonmathematician readers? ;-) – Gonzalo Medina Dec 03 '14 at 13:16
One could endeavor to refrain from using "co" even in category theory by continually switching between opposite categories :p – Exterior Dec 03 '14 at 13:16
@GonzaloMedina Hence my comment "Nevermind then" :P – percusse Dec 03 '14 at 13:17

Macros for image, coimage, and cokernel

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