  In sequential logic there is an order in which the atomic propositions in an
expression are evaluated. This order allows the same atomic proposition to have
different values depending on which atomic propositions have already been
evaluated. In the sequential propositional logic discussed in this thesis, such
valuations are called "reactive" valuations, in contrast to "static" valuations
as are common in e.g. ordinary propositional logic. There are many classes of
these reactive valuations e.g., we can define a class of reactive valuations
such that the value for each atomic proposition remains the same until another
atomic proposition is evaluated. This Master of Logic thesis consists of a
study of some of the properties of this logic. We take a closer look at some of
the classes of reactive valuations. We particularly focus on the relation
between the axiomatization and the semantics. Consequently, the main part of
this thesis focuses on proving soundness and completeness. Furthermore, we show
that the axioms in the provided axiomatizations are independent i.e., there are
no redundant axioms present. Finally, we show {\omega}-completeness for two
classes of reactive valuations.
