Abstract: Cagri will talk about some symplectic/contact topological aspects of Brieskorn singularities $x^p+y^q+z^r=0$. He’ll tell how to draw the surgery diagrams of their canonical contact structures and prove that the Milnor fiber $M(p,q,r)$ symplectically embeds into $M(p’,q’,r’)$ whenever $p\leq p’$, $q\leq q’$, and $r\leq r’$ by explicitly constructing a Stein cobordism between corresponding canonical contact structures. In the reverse direction, contact Heegaard-Floer invariant sometimes obstructs the existence of Stein cobordisms between certain types of singularities. When p=q=r, exchanging the Milnor fiber with the minimal resolution of the  singularity gives an interesting relationship in the mapping class group and defines a new interpretation of certain symplectic sum operation on four-dimensional manifolds. The talk is based on his recent joint work with Akhmedov and Sakalli. The seminar will be held on Zoom. Contact sdey4@ua.edu for the link to the Zoom.