  In this work we study opinion formation on a fully-connected population
participating of a public debate with two distinct choices, where the agents
may adopt three different attitudes (favorable to either one choice or to the
other, or undecided). The interactions between agents occur by pairs and are
competitive, with couplings that are either negative with probability $p$ or
positive with probability $1-p$. This bimodal probability distribution of
couplings produces a behavior similar to the one resulting from the
introduction of Galam's contrarians in the population. In addition, we consider
that a fraction $d$ of the individuals are intransigent, that is, reluctant to
change their opinions. The consequences of the presence of contrarians and
intransigents are studied by means of computer simulations. Our results suggest
that the presence of inflexible agents affects the critical behavior of the
system, causing either the shift of the critical point or the suppression of
the ordering phase transition, depending on the groups of opinions
intransigents belong to. We also discuss the relevance of the model for real
social systems.
