TY - JOUR
T1 - An explicit formula for a Bennequin-type invariant for apparent contours
AU - Paolini, Maurizio
AU - Bellettini, Giovanni
AU - Beorchia, Valentina
PY - 2009
Y1 - 2009
N2 - We derive an explicit formula for the computation of a Vassiliev-type invariant of an apparent contour introduced recently by Ohmoto and Aicardi using appropriate linking numbers of its Legendrian lift. Our formula does not require the construction of the Legendrian lift and only takes into account the nodes, the cusps, the extremal points and the orientation of the apparent contour. In this way the computation can be implemented into a computer program; we demonstrate its use with some examples.
AB - We derive an explicit formula for the computation of a Vassiliev-type invariant of an apparent contour introduced recently by Ohmoto and Aicardi using appropriate linking numbers of its Legendrian lift. Our formula does not require the construction of the Legendrian lift and only takes into account the nodes, the cusps, the extremal points and the orientation of the apparent contour. In this way the computation can be implemented into a computer program; we demonstrate its use with some examples.
KW - apparent contours
KW - vassiliev invariants
KW - apparent contours
KW - vassiliev invariants
UR - http://hdl.handle.net/10807/11409
U2 - 10.1016/j.topol.2008.09.011
DO - 10.1016/j.topol.2008.09.011
M3 - Article
SN - 0166-8641
SP - 747
EP - 760
JO - Topology and its Applications
JF - Topology and its Applications
ER -