The software chooses a basis of the lattice X_*(T). The "coroots"
command prints out the list of all the coroots for the group,
in this basis. See the help file for the roots command.
If G is defined using the "sc" (respectively "ad") option to be simply
connected (resp. adjoint) this basis is the basis of simple coroots
(resp. simple fundamental coweights), plus a copy of Z^n if G is not
semisimple. In general this basis may be fairly arbitrary and
difficult to understand. This command is useful in understanding this
basis for use with other commands.
The "coroots_rootbasis" command gives all coroots in the basis of
simple coroots. See also roots, roots_rootbasis, posroots,
posroots_rootbasis, poscoroots, poscoroots_rootbasis and rootdatum.