  Because of the limitations of classical silicon based computational
technology, several alternatives to traditional method in form of
unconventional computing have been proposed. In this paper we will focus on DNA
computing which is showing the possibility of excellence for its massive
parallelism, potential for information storage, speed and energy efficiency. In
this paper we will describe how syllogistic reasoning by DNA tweezers can be
presented by the semantics of process calculus and DNA strand graph. Syllogism
is an essential ingredient for commonsense reasoning of an individual. This
paper enlightens the procedure to deduce a precise conclusion from a set of
propositions by using formal language theory in form of process calculus and
the expressive power of DNA strand graph.
