Systems of functions with the dual orthogonality property

A method is specified for constructing systems of functions with the property of orthogonality with respect to two different sets.Translated from Matematicheskie Zametki, Vol. 4, No. 5, pp. 551–556, November, 1968.     

Two-parameter experimental investigation of co-existing oscillation modes in torus breakdown

The onset of to chaos in a quasiperiodic piecewise-linear two-frequency oscillator is studied by experiments and numerical simulation. The fine structure of the multistable behavior of the phaselocking regions of Arnold's tongues near the Hopf bifurcation line is plotted in a two-parameter bifurcation diagram.Scientific and Educational Center Kolledzh, State University, Saratov. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 38, No. 11, pp. 1195–1203, November, 1995.