Irina Starikova (Sao Paulo) gives a talk at the MCMP Colloquium (8 January, 2015) titled "Symmetry and Mathematicians' Aesthetic Preferences: a Case Study". Abstract: Symmetry plays an important role in some areas of mathematics and has traditionally been regarded as a factor of visual beauty. In this talk I explore the ways that symmetry contribute to mathematicians’ aesthetics judgments about mathematical entities and representations. I discuss an example from algebraic graph theory. Comparing two isomorphic drawings of the Petersen graph, I argue that we need to refine the question by distinguishing between perceptual and intellectual beauty and by noting that some mathematical symmetries are revealed to us in diagrams while others are hidden.