Journal of Singularities
volume 12 (2015), 1-18
Received 3 April 2014. Received in revised form 11 January 2015.
We obtain a list of all simple classes of singularities of function germs with respect to the quasi cusp equivalence relation. We discuss its connection with the singularities of Lagrangian projections in presence of a cuspidal edge. We also describe the bifurcation diagrams and caustics of simple quasi cusp singularities.
Quasi border singularities, cusp, bifurcation diagram, caustic, Lagrangian projection
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