[1] Univ Andes, Dept Math, Carrera 1 18A-12 CP 11711, Bogota, Colombia
[2] Univ Norte, Dept Math & Stat, Km 5 Via Puerto Colombia,CP 080003, Barranquilla, Colombia
[3] HSE Univ, Moscow, Russia
[4] Ctr Invest Matemat, Guanajuato, Mexico
[5] Ctr Invest Matemat AC, Dept Probabil & Stat, Calle Jalisco S-N,CP 36240, Guanajuato, Mexico
[6] Kansai Univ, Fac Engn Sci, Dept Math, 3-3-35 Yamate Cho, Suita, Osaka 5648680, Japan