  We discuss two models of opinion dynamics. First wepresent a brief review of
the Hegselmann and Krause (HK) compromise model in two dimensions, showing that
it is possible to simulate the dynamics in the limit of an infinite number of
agents by solving numerically a rate equation for a continuum distribution of
opinions. Then, we discuss the Opinion Changing Rate (OCR) model, which allows
to study under which conditions a group of agents with a different natural
tendency (rate) to change opinion can find the agreement. In the context of the
this model, consensus is viewed as a synchronization process.
