# About renewcommand [duplicate]

I'm new to LaTeX and I was wondering how to write a command that gives me \left\{A,B\right\}. I want to renew this command like \poisson, for example.

If someone could help me, I will be very grateful.

Sorry if the question is basic.

Thanks.

• Package physics already has \pb{A}{B}. – Johannes_B May 20 '17 at 5:18
• Sometimes defining a simple command can do the job, sometimes using one of the thousands of packages adding extra functionality to basic LaTeX can do the job. Depends. – Johannes_B May 20 '17 at 5:19