Exact estimates of types of entire functions of an order $\rho\in(0;1)$ with zeroes on the ray

This paper is a detailed account of the author's report made during VI Ufa international conference “Complex analysis and differential equations”, devoted to the 70-th anniversary of Corresponding member of RAS V. V. Napalkov. Sharp lower estimates of an entire function type of a finite order with respect to such wellknown characteristics of the distribution of its zeros as the density (conventional and average), step and lacunarity index. The solution of one new extremal problem is also given.