3 papers
math.NT2025
Modular differential equations and orthogonal polynomials
Khalil Besrour, Hicham Saber, Abdellah Sebbar
We study second-order modular differential equations whose solutions transform equivariantly under the modular group. In the reducible case, we construct all such solutions using a…
math.NT2025
Higher Schwarzian, quasimodular forms and equivariant functions
Hicham Saber, Abdellah Sebbar
The Schwarzian derivative plays a fundamental role in complex analysis, differential equations, and modular forms. In this paper, we investigate its higher-order generalizations, k…
math.CO2025
On a Conjecture Concerning the Complementary Second Zagreb Index
Hicham Saber, Tariq Alraqad, Akbar Ali +2
The complementary second Zagreb index of a graph is defined as , where denotes the degree of a vertex in and…