São Paulo, July 28, 2018.

Prof. Dr. Claudio GorodskiCo-Chair of the Organizing Commitee

This is to certify that

Abraão Caetano Mendes

participated in the Modern Trends in Differential Geometry, held in São Paulo, from July 23th to 27th, 2018 at

the Institute of Mathematics and Statistics of University of São Paulo, São Paulo - Brazil, and presented the

poster Generic simplicity of the eigenvalues of the drifting Laplacian on compact Riemannian manifolds.