%0 Journal Article %T Symmetry in Generating Functions %A Shigeru Watanabe %J Symmetry %D 2010 %I MDPI AG %R 10.3390/sym2010345 %X Generating functions play important roles in theory of orthogonal polynomials. In particular, it is important to consider generating functions that have symmetry. This paper is a survey on generating functions that define unitary operators. First, classical generating functions that define unitary operators are discussed. Next, group theoretical approach to generating functions that have unitarity are discussed. %K Generating function %K Orthogonal polynomial %K Zonal spherical function %U http://www.mdpi.com/2073-8994/2/1/346