Abstract:
Two main results of this paper are singled out. The first one relates to the representation theory of symmetric groups. The second one deals with varieties of Lie algebras over a field of characteristic zero. The first result can be presented as follows: given a symmetric group of sufficiently large degree $n$, every irreducible representation of it with Young diagram fitting into a square with side $n/k$ is of dimension at least $k^n$. The second result states that there are no varieties of Lie algebras over a field of characteristic zero with lower exponent strictly less than two. At the same time, examples of varieties with exponent two are presented.