  The authors found geodesics, shortest arcs, cut loci, and conjugate sets for
left-invariant sub-Riemannian matric on the Lie group $SL(2)$, which is
right-invariant relative to the Lie subgroup $SO(2)\subset SL(2)$ (in other
words, for invariant sub-Riemannian metric on weakly symmetric space
$(SL(2)\times SO(2))/SO(2)$).
