** M. Afkhami, K. Khashyarmanesh and F. Shahsavar**
On the properties of zero-divisor graphs of posets, pp.1-16

** W. Atiponrat and R. Maungchang**
Continuous homomorphisms, the left-gyroaddition action and topological quotient gyrogroups, pp.17-28

** G. Biyogmam, S. Tchamna and C. Tcheka**
From quotient trigroups to groups, pp.29-41

** M. Borralho**
The transitivity of primary conjugacy in a class of semigroups, pp.43-46

** S.S. Davidov and D.A. Shahnazaryan**
Hyperidentities with permutations leading to the isotopy
of invertible binary algebras to a group, pp.47-52

** W.A. Dudek and R.A.R. Monzo**
Translatability determines the structure
of certain types of idempotent quasigroups, pp.53-76

** K. Hansda and A. Jamadar**
Characterization of inverse ordered semigroups
by their ordered idempotents and bi-ideals, pp.77-88

** A. Hasanvand and R. Rezaei**
The equivalence graph of the comaximal graph of a group, pp.89-100

** M. Hassanzadeh and S. Sutlu**
Matched pairs of m-invertible Hopf quasigroups, pp.101-138

** T. Imran, M. Ashiq and M.A. Zaighum**
Computational approach for intransitive action of Delta(2,4,k) on PL(F

_{q}), pp.139-148

** S. Kar, A. Roy and I. Dutta**
On regularities in po-ternary semigroups, pp.149-158

** H.B. Shelash and A.R. Ashrafi**
Table of marks and markaracter table of certain finite groups, pp.159-170

### vol.28 (2020) No. 2