We describe an explicit simulation of 2-way nondeterministic automata by 1-way alternating automata with quadratic blow-up. We first describe the construction for automata on finite words, and extend it to automata on infinite words.

Proving termination of sequential programs is an important problem, both for establishing the total correctness of systems and as a component of proving more general termination and liveness properties. We present a new algorithm, TREX, that determines if a sequential program terminates on all inputs. The key characteristic of TREX is that it alternates between refining an overapproximation and...

In this paper we consider several notions of alternation in cellular automata: non-uniform, uniform and weak alternation. We study relations among these notions and with alternating Turing machines. It is proved that the languages accepted in polynomial time by alternating Turing machines are those accepted by alternating cellular automata in polynomial time for all the proposed alternating cel...

It has been noted repeatedly that although many verbs do occur in both syntactic patterns, some verbs only occur in one of the two patterns. For example, verbs such as cost and deny are widely described as occurring only with the DO construction whereas verbs such as drag and yell only with the PO construction. In addition, although certain verbs have been observed in both syntactic patterns, t...

CHEST, 69: 6, JUNE, 1976 ALTERNATION OF LEFT VENTRICULAR PERFORMANCE 191 7 Bryant LR, Eiseman B: Experimental evaluation of intercoastal pedicle grafts in esophageal repair. J Thorac Cardiovasc Surg 50:626, 1965 8 Efthimiadis M, Xanthakis D, Primikyrios N, et al: Late esophagopleural fistula after pneumonectomy for bronchial carcinoma. Chest 65:579-580, 1974 9 Clagett OT, Geraci JE: A procedure...

We introduce a new class Op2 as a subclass of the symmetric alternation class Sp2. An O p 2 proof system has the flavor of an S p 2 proof system, but it is more restrictive in nature. In an Sp2 proof system, we have two competing provers and a verifier such that for any input, the honest prover has an irrefutable certificate. In an Op2 proof system, we require that the irrefutable certificates ...

Organisms ranging from paramecia to humans tend to explore places that have been least recently explored, which is referred to as spontaneous alternation. Although organisms rely on different sources of information in alternating between places, the emergent behavioral pattern is likely advantageous during exploration and foraging. Under this rationale, continuous spontaneous alternation perfor...

One mechanism by which administration of glucose enhances cognitive functions may be by modulating central ATP-sensitive potassium (K-ATP) channels. K-ATP channels appear to couple glucose metabolism and neuronal excitability, with channel blockade increasing the likelihood of neurosecretion. The present experiment examined the effects of glucose and the direct K-ATP channel modulators glibencl...

Following Fillmore’s (1968) discussion of verbs exhibiting different argument realization patterns, a number of syntactic studies have analyzed the spray-load alternation (e.g., Pinker 1989, Levin 1993, Dowty 2000) in different ways. One account that differs from primarily syntactically oriented analyses is Goldberg’s (1995) Construction Grammar approach. It proposes that multiple argument real...

It is known that the alternation hierarchy of least and greatest fixpoint operators in the μ-calculus is strict. However, the strictness of the alternation hierarchy does not necessarily carry over when considering restricted classes of structures. A prominent instance is the class of infinite words over which the alternation-free fragment is already as expressive as the full μ-calculus. Our cu...