  Interval type-2 fuzzy logic systems (IT2 FLSs) have a wide range of
applications due to their abilities to handle uncertainties compared to their
type-1 counterparts. This paper discusses the representation of IT2 FLSs in
closed mathematical form. Two novel inference mechanisms are introduced, each
of them represents a whole IT2 FLS. The two forms are based on approximating
Coupland and John's geometric method and the Nie-Tan method. Having closed-form
representations is preferred in the design of control systems, especially when
stability analysis is studied. Additionally, the simplicity of the proposed
mechanisms, offers an easy way for implementation. Simulation results show that
the proposed method perform very closely to other methods. Simulation results
are provided.
