Exponential bulges and antitruncated disks in lenticular galaxies

The presence of exponential bulges and anti-truncated disks has been noticed in many lenticular galaxies. In fact, it could be expected because the very formation of S0 galaxies includes various processes of secular evolution. We discuss how to distinguish between a pseudobulge and an anti-truncated disk, and also what particular mechanisms may be responsible for the formation of anti-truncated disks. Some clear examples of lenticular galaxies with a multi-tier exponential stellar structure are presented, - among them two central group giant S0s seen face-on and perfectly axisymmetric.