%0 Conference Article %T GEOMETRIC METHOD FOR ANALYZING THE EXISTENCE OF A PERIODIC SOLUTION TO A DIFFERENTIAL EQUATION %A Korotkih, A.S. %K differential equation, periodic solution, shift operator %J OPERATOR EQUATIONS AND SOME RELATED ISSUES IN APPLIED MATHEMATICS %D 2026 %P 5 %I FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov