  In this note we present a brief introduction to Lagrangian Floer homology and
its relation with the solution of Arnol'd conjecture, on the minimal number of
non-degenerate fixed points of a Hamiltonian diffeomorphism. We start with the
basic definition of critical point on smooth manifolds, in oder to sketch some
aspects of Morse theory. Introduction to the basics concepts of symplectic
geometry are also included, with the idea of understanding the statement of
Arnol'd Conjecture and how is related to the intersection of Lagrangian
submanifolds.
