Deterministic fuzzy two-dimensional on-line tessellation automata and their languages

The main work of this paper is to extend deterministic two-dimensional on-line tessellation automata (D2OTAs) to the fuzzy setting. We call these new automata models deterministic fuzzy two-dimensional on-line tessellation automata (DF2OTAs) and focus on some of their properties. Concretely, we firstly give the definitions of DF2OTAs and the fuzzy picture languages recognized by them. Next, the closure properties of the collection of fuzzy picture languages recognized by DF2OTAs are concentrated on under some familiar operations. The decomposition theorem, the representation theorem and the Pumping lemma, which are studied in the theory of fuzzy string automata and the related languages, are also considered scrupulously in the framework of DF2OTAs and their languages. Then, we put forward the concepts of transition-accessible DF2OTAs and state-accessible DF2OTAs, and conclude that transition-accessible DF2OTAs are special state-accessible DF2OTAs and DF2OTAs are equivalent to state-accessible DF2OTAs. Finally, state reduction relations on state-accessible DF2OTAs are defined to study the problem of the state reduction of DF2OTAs. Given a state-accessible DF2OTA $A$, in order to construct the factor DF2OTA of $A$ with respect to a state reduction relation on $A$ such that this factor one is equivalent to $A$ and possesses a fewer states, we design a polynomial-time algorithm to compute the largest state reduction relation and then construct the corresponding factor automaton.