Solutions to the Thin Obstable Problem with non-2D frequency

Abstract: I will explain the relationship between the thin obstacle problem and two "unsigned" versions: 2-valued C^{1,alpha} stationary harmonic functions and Z/2Z harmonic functions. I will then present a simple construction of homogeneous solutions to the thinobstacle problem with non-2D frequency, recently obtained in collaboration with Ovidiu Savin.