[en] The confinement phase transition is studied. The relation between the decay rates of the Wilson loop integral, Osterwalder and Seiler's n-ality restriction, and Polyakov and 't Hooft's analysis of the center of the gauge group is pointed out. Vortices and merons are analyzed as possible mechanisms to produce disorder in the center. It is shown how to realize the t' Hooft commutation relations, and the critical coupling for vortices to be in approximate agreement with the critical coupling determined by Callan, Dashen and Gross is estimated from the analysis of instantons. (Auth.)