  Most merging operators are defined by semantics methods which have very high
computational complexity. In order to have operators with a lower computational
complexity, some merging operators defined in a syntactical way have be
proposed. In this work we define some syntactical merging operators and
exploring its rationality properties. To do that we constrain the belief bases
to be sets of formulas very close to logic programs and the underlying logic is
defined through forward chaining rule (Modus Ponens). We propose two types of
operators: arbitration operators when the inputs are only two bases and fusion
with integrity constraints operators. We introduce a set of postulates inspired
of postulates LS, proposed by Liberatore and Shaerf and then we analyzed the
first class of operators through these postulates. We also introduce a set of
postulates inspired of postulates KP, proposed by Konieczny and Pino P\'erez
and then we analyzed the second class of operators through these postulates.
