Some algebraic structures in KPZ universality

We review some algebraic and combinatorial structures that underlie models in the KPZ universality class. Emphasis is given on the Robinson-Schensted-Knuth correspondence and its geometric lifting due to A.N.Kirillov and we present how these are used to analyse the structure of solvable models in the KPZ class and lead to computation of their statistics via connecting to representation theoretic objects such as Schur, Macdonald and Whittaker functions. We also present how fundamental representation theoretic concepts, such as the Cauchy identity, the Pieri rule and the branching rule can be used, alongside RSK correspondences, and can be combined with probabilistic ideas, in order to construct stochastic dynamics on two dimensional arrays called Gelfand-Tsetlin patterns, in ways that couple different one dimensional stochastic processes. The goal of the notes is to expose some of the overarching principles, that have driven a significant number of developments in the field, as a unifying theme.