en تخصصي Special پژوهشي Research paper <div style="text-align: justify;">In this paper, we consider quasi-eqilibrium problems which extend equilibrium problems and quasi-variational inequalities as well as variational inequalities in Hadamard spaces. We study ∆-convergence of the sequence generated by the extragradient method to a solution of a quasi-equilibrium problem in Hadamard spaces. Then we show strong convergence of the generated sequence to a solution of the problem by imposing some additional conditions. We also use the Halpern regularization method to prove strong convergence of the generated sequence to a solution of the quasi-equilibrium problem where the equilibrium point is the projection of an arbitrary point u onto the solution set of the problem.</div> Extragradient method, Halpern regularization, Multivalued mapping, Quasi-equilibrium problem, Quasi-nonexpansive. 139 154 http://ijmsi.ir/browse.php?a_code=A-10-6381-1&slc_lang=en&sid=1 Mehdi Mohammadi mehdi.mohammadi5677@gmail.com 100319475328460011696 100319475328460011696 Yes Department of Mathematics, Payame Noor University, Tehran, Iran G. Zamani Eskandani zamani@tabrizu.ac.ir 100319475328460011697 100319475328460011697 No Department of Pure Mathematics, Faculty of Mathematical Sciences, University of Tabriz, Tabriz, Iran