(1)
Department of Mathematics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Kampus Baru UI, Depok 16424, Indonesia ,
(2)
Department of Mining Engineering, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Jalan Ganesa 10 Bandung 40132, Indonesia ,
(3)
Department of Mathematics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Kampus Baru UI, Depok 16424, Indonesia ,
(4)
Department of Mathematics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Kampus Baru UI, Depok 16424, Indonesia