Full paper in PDF:
$%F. Aicardi, Remarks on the symmetries of planar fronts, Rev. Mat. Univ. Complut. Madrid 8 (1995), no. 2, 355–378.%$

A front is the projection on the plane of a Legendrian immersion of a circle in the space of the contact elements of that plane. I analyze the symmetries of a generic front with respect to the group generated by the involutions reversing the orientation of the plane, the orientation of the preimage circle and the coorientation of the contact plane.

1991 Mathematics Subject Classification: 53A04, 57M25, 58F05.