as others remark, there are no standard compose rules in X for π, so if you want to use compose to make the π symbol (as I just did), you could:
- install uim
- create
~/.XCompose - put there the rules you need
- do not forget to start the file with
include "%L"
mine looks like this:
include "%L"
<Multi_key> <l> <l> : "ℓ" U2113 # litre symbol
<Multi_key> <p> <i> : "π" U03C0 # GREEK SMALL LETTER PI
this works on Debian. it does affect the way Ctrl-Shift-u works.