provide group order as a type encompassing the Infinity

[kalmarek]

Option to discuss:

• comparing orders and numbers
• no arithmetics (promotion rules), you need to convert to a number explicitly

e.g.
https://gist.github.com/kalmarek/640630a53d5837a5c7fe401eb2f047bd

[thofma]

With the small union splitting in place, one can get pretty good performance by just using a singleton for positive infinity. We are using this in Hecke valuations, and I plan to move this to AbstractAlgebra.

(Just FYI).

[kalmarek]

is is being discussed somewhere?
if union splitting is considered, then why not just return an Inf?