**TOME 64 (112), no. 1, 2021****Djamel Benterki, Adnan Yassine, Amina Zerari:**Interior-point algorithm for semidefinite programming based on a logarithmic kernel function, 3-17**Merouani Boubakeur, Zoubai Fayrouz:**A nonlinear elasticity system in Sobolev spaces with variable exponents, 17-33**Raul Epure, Delphine Pol:**On constructions of free singularities, 35-48**I-Chiau Huang:**An algebraic approach to residues, 49-62**Dorin Popescu:**Valuation rings of dimension one as limits of smooth algebras, 63-73**Xiaoer Qin, Li Yan:**Some generalized permutation polynomials over finite fields, 75-87**Zoran Stanic, Ambat Vijayakumar:**On spectral radius of signed graphs without negative even cycles, 79-96**Yiqiang Zhou:**A note on UN-rings, 97-100