binding C-uC-SPC to a new key

[Badari Kakumani]

folks,

i would appreciate pointers to invoke the the set-mark-command
with a prefix (so that it traverses back to where previous mark was).

i tried:

    (define-key alt-m-map "p" '(lambda ()
((universal-argument)(set-mark-command))))

but the above didn't work. yes, i am newbie to elisp ;)

thanks,
-badari