||In representation theory, trace formulas are used to calculate the traces of certain linear operators. The formulas relate geometric side and spectral side. In mathematics and physics, analog of the concepts of geometric side vs spectral side appears quite often. In quantum mechanics, we have particles vs waves. In the theory of the Riemann zeta function we
have primes vs zeros. In differential geometry, we have geodesics vs eigenvalue of Laplacians. In the talk, we will discuss these phenomena and give a basic introduction
to trace formula.