Realizability of Singular Levels of Morse Functions as Unions of Geodesics / I. N. Shnurnikov. // Vestnik Moskovskogo Universiteta. Seriya 1. Matematika. Mekhanika. 2015. № 6. P. 45-48 [Moscow Univ. Math. Bulletin. Vol. 72, N 2, 2017. P. 270-273].

The paper presents a list of special graphs of degree 4 with at most 3 vertices (atoms from the theory of integrable Hamiltonian systems) which could be represented by a union of closed geodesics in one of the following surfaces with a metric of constant curvature: sphere, projective plane, torus, and Klein bottle.

Key words: 2-atom, closed geodesics, metric of constant curvature.