While the complexity of translating future linear temporal logic (LTL) into automata on infinite words is well-understood, size increase involved in turning back to LTL not. In particular, there no known elementary bound deterministic $\omega$-regular LTL. Our first contribution consists tight bounds for over a unary alphabet: alternating, nondeterministic and can be exactly exponentially, quad...

In Hartmanis (1980) a simple proof is given of the fact (originally proved in Valiant (1976)) that the relative succinctness of representing deterministic context-free languages by deterministic vs. nondeterministic pushdown automata is not recursively bounded, in the following sense: there is no recursive function which, for deterministic context-free languages L, can bound the size of the min...

In this paper, we outline the design of a nondeterministic finite state automaton (NFSA) for natural language morphology, and compare it to previous work in unsupervised learning of morphology. In Section 2, we describe the nature of an MDL-based system for unsupervised learning of morphology, using the signature-based model of Goldsmith 2001 as an example, and we describe some drawbacks of the...

We propose and evaluate a new algorithm for checking the universality of nondeterministic finite automata. In contrast to the standard algorithm, which uses the subset construction to explicitly determinize the automaton, we keep the determinization step implicit. Our algorithm computes the least fixed point of a monotone function on the lattice of antichains of state sets. We evaluate the perf...

An iterative array is a line of interconnected interacting finite automata. One distinguished automaton, the communication cell, is connected to the outside world and fetches the input serially symbol by symbol. Sometimes in the literature this model is referred to as cellular automaton with sequential input mode. We are investigating iterative arrays with a nondeterministic communication cell....

Abstract Symbiotic-Witch is a new tool for checking violation witnesses in the GraphML-based format used at SV-COMP since 2015. Roughly speaking, symbolically executes given program with Klee and simultaneously tracks set of nodes witness automaton can be in. Moreover, it reads return values nondeterministic functions specified uses them to prune symbolic execution. The confirmed if execution r...

The complexity and decidability of various decision problems involving the shuffle operation (denoted by ) are studied. The following three problems are all shown to be NP-complete: given a nondeterministic finite automaton (NFA) M , and two words u and v, is L(M) 6⊆ u v, is u v 6⊆ L(M), and is L(M) 6= u v? It is also shown that there is a polynomial-time algorithm to determine, for NFAs M1,M2 ...

The paper gives an example of a tree language G that is recognised by an unambiguous parity automaton and is Σ1-complete (analytic-complete) as a set in Cantor space. This already shows that the unambiguous languages are topologically more complex than the deterministic ones, that are all in Π1. Using set G as a building block we construct an unambiguous language that is topologically harder th...

Abstract We consider the notion of a constant length queue automaton —i.e., traditional with built-in limit on its queue—as formalism for representing regular languages. show that descriptional power automata greatly outperforms finite state automata, height pushdown and straight line programs expressions, by providing optimal exponential double-exponential size gaps. Moreover, we prove can be ...

We study three notions of directability of fuzzy automata akin to the D1-, D2and D3-directability of nondeterministic automata. Thus an input word w of a fuzzy automaton is D1-directing if a fixed single state is reachable by w from all states, D2-directing if exactly the same states are reachable by w from every state, and D3-directing if there is a state reachable by w from every state. We st...