Math & Science ⇒ Defining math operators that accept input.

[dtmurphree]

I am writing a paper that requires arbitrary R-module homomorphism groups Hom_R(*,X) and Hom_R(X,*)to be typed frequently. I would like to declare math operators that take input so that I can type "\rHom{B}" and have the output "Hom_R(B,X)" and type "\lHom{A}" and have the output "Hom_R(X,A)". So far the best I can come up with still requires me to type out the _R(B,X) part.

[kaiserkarl13]

I am writing a paper that requires arbitrary R-module homomorphism groups Hom_R(*,X) and Hom_R(X,*)to be typed frequently. I would like to declare math operators that take input so that I can type "\rHom{B}" and have the output "Hom_R(B,X)" and type "\lHom{A}" and have the output "Hom_R(X,A)". So far the best I can come up with still requires me to type out the _R(B,X) part.

I'm having to guess somewhat as to what you want the input commands to be, but how about this:

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\newcommand*{\rHom}[2]{\mathrm{Hom_R}(#1,#2)}
\newcommand*{\lHom}[2]{\mathrm{Hom_R}(#2,#1)}

Then you would type

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  \rHom{B}{X} \lHom{A}{X}

to get "Hom_R(B,X) Hom_R(X,A)"

[dtmurphree]

I am writing a paper that requires arbitrary R-module homomorphism groups Hom_R(*,X) and Hom_R(X,*)to be typed frequently. I would like to declare math operators that take input so that I can type "\rHom{B}" and have the output "Hom_R(B,X)" and type "\lHom{A}" and have the output "Hom_R(X,A)". So far the best I can come up with still requires me to type out the _R(B,X) part.

I'm having to guess somewhat as to what you want the input commands to be, but how about this:

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\newcommand*{\rHom}[2]{\mathrm{Hom_R}(#1,#2)}
\newcommand*{\lHom}[2]{\mathrm{Hom_R}(#2,#1)}

Then you would type

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  \rHom{B}{X} \lHom{A}{X}

to get "Hom_R(B,X) Hom_R(X,A)"

Thank you so much! This was almost exactly what I was looking for, and close enough for me to get what to do next. I kept trying to do it as a

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\DeclareMathOperator

instead of a whole new command!

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\newcommand*{\rHom}[1]{\mathrm{Hom_R}(#1,X)}
\newcommand*{\lHom}[1]{\mathrm{Hom_R}(X,#1)}

was just what the doctor ordered and saves quite a few key strokes per hour!