Infinite distohastic square operators in li

The article is devoted to bistochastic quadratic operators. The concept of a bistochastic quadratic operator is introduced and the property of such operators is studied. A necessary and sufficient condition for bistochasticity is given. An analogue of Birkhoff s theorem is studied for the class of bistochastic quadratic operators. A sufficient condition for the extremity of bistochastic quadratic operators is obtained, and a necessary condition is also obtained for small dimensions. The concept of bistochastic quadratic operators is generalized, and the concept of a bistochastic operator of arbitrary order is introduced. Contribution of the authors: the authors contributed equally to this article. The authors declare no conflicts of interests.