LOWER BOUND FOR THE INDEX OF CONVERGENCE OF THE SINGULAR INTEGRAL IN A MULTIDIMENSIONAL ANALOGUE OF TARRY'S PROBLEM Article Chakhkiev M.A., Tretyakov N.P., Mouhammad S.A. Italian Journal of Pure and Applied Mathematics. Forum-Editrice Universitaria Udinese SRL. Vol. 48. 2022. P. 433-438