Li Guo: Separable Volterra operators and generalized Reynolds algebras

The Reynolds operator originated from the well-known work of Reynolds on fluid mechanics in the late 19th century. The classical example of a Reynolds operator is given by a specific Volterra integral operator, first studied by Reynolds and Rota. In this study, we explore the rich algebraic structures from other Volterra integral operators, when the kernel of the operator is separable. The operator satisfies a generalized Reynolds identity, called the D-differential Reynolds identity. To construct the corresponding free objects, we develop a completion for topological operated algebras and define a completion of the shuffle product. The construction provides an algebraic framework to define and study Volterra integral equations with separable kernels. This is a joint work with Richard Gustavson and Yunnan Li.