On the Expressive Power of Non-deterministic and Unambiguous Petri Nets over Infinite Words

We prove that ω-languages of (non-deterministic) Petri nets and ω-languages of (nondeterministic) Turing machines have the same topological complexity: the Borel and Wadge hierarchies of the class of ω-languages of (non-deterministic) Petri nets are equal to the Borel and Wadge hierarchies of the class of ω-languages of (non-deterministic) Turing machines. We also show that it is highly undecidable to determine the topological complexity of a Petri net ω-language. Moreover, we infer from the proofs of the above results that the equivalence and the inclusion problems for ω-languages of Petri nets are ∏21-complete, hence also highly undecidable. Additionally, we show that the situation is quite the opposite when considering unambiguous Petri nets, which have the semantic property that at most one accepting run exists on every input. We provide a procedure of determinising them into deterministic Muller counter machines with counter copying. As a consequence, we entail that the ω-languages recognisable by unambiguous Petri nets are △30 sets.

Affine Extensions of Integer Vector Addition Systems with States

We study the reachability problem for affine $\mathbb{Z}$-VASS, which are integer vector addition systems with states in which transitions perform affine transformations on the counters. This problem is easily seen to be undecidable in general, and we therefore restrict ourselves to affine $\mathbb{Z}$-VASS with the finite-monoid property (afmp-$\mathbb{Z}$-VASS). The latter have the property that the monoid generated by the matrices appearing in their affine transformations is finite. The class of afmp-$\mathbb{Z}$-VASS encompasses classical operations of counter machines such as resets, permutations, transfers and copies. We show that reachability in an afmp-$\mathbb{Z}$-VASS reduces to reachability in a $\mathbb{Z}$-VASS whose control-states grow linearly in the size of the matrix monoid. Our construction shows that reachability relations of afmp-$\mathbb{Z}$-VASS are semilinear, and in particular enables us to show that reachability in $\mathbb{Z}$-VASS with transfers and $\mathbb{Z}$-VASS with copies is PSPACE-complete. We then focus on the reachability problem for affine $\mathbb{Z}$-VASS with monogenic monoids: (possibly infinite) matrix monoids generated by a single matrix. We show that, in a particular case, the reachability problem is decidable for this class, disproving a conjecture about affine $\mathbb{Z}$-VASS with infinite matrix monoids we raised in a preliminary version of this paper. We complement this result by presenting an affine $\mathbb{Z}$-VASS with monogenic matrix monoid and undecidable reachability relation.

LTL-Specification of Counter Machines

The article is written in support of the educational discipline “Non-classical logics”. Within the framework of this discipline, the objects of study are the basic principles and constructive elements, with the help of which the formal construction of various non-classical propositional logics takes place. Despite the abstractness of the theory of non-classical logics, in which the main attention is paid to the strict mathematical formalization of logical reasoning, there are real practical areas of application of theoretical results. In particular, languages of temporal modal logics are widely used for modeling, specification, and verification (correctness analysis) of logic control program systems. This article demonstrates, using the linear temporal logic LTL as an example, how abstract concepts of non-classical logics can be reƒected in practice in the field of information technology and programming. We show the possibility of representing the behavior of a software system in the form of a set of LTL-formulas and using this representation to verify the satisfiability of program system properties through the procedure of proving the validity of logical inferences, expressed in terms of the linear temporal logic LTL. As program systems, for the specification of the behavior of which the LTL logic will be applied, Minsky counter machines are considered. Minsky counter machines are one of the ways to formalize the intuitive concept of an algorithm. They have the same computing power as Turing machines. A counter machine has the form of a computer program written in a high-level language, since it contains variables called counters, and conditional and unconditional jump operators that allow to build loop constructions. It is known that any algorithm (hypothetically) can be implemented in the form of a Minsky three-counter machine.

Weak Cost Register Automata are Still Powerful

We consider one of the weakest variants of cost register automata over a tropical semiring, namely copyless cost register automata over [Formula: see text] with updates using [Formula: see text] and increments. We show that this model can simulate, in some sense, the runs of counter machines with zero-tests. We deduce that a number of problems pertaining to that model are undecidable, namely equivalence, upperboundedness, and semilinearity. In particular, the undecidability of equivalence disproves a conjecture of Alur et al. from 2012. To emphasize how weak these machines are, we also show that they can be expressed as a restricted form of linearly-ambiguous weighted automata.

Application of Chopper Machinery Technology from Oil Palm Fronds in Huta Gondang Rejo Nagori Bandar Tongah Bandar Hands, Regency of Simalungun

This community service activity aims to improve the efficiency of cattle farm business in Huta Gondang Rejo Nagori Bandar Tongah Bandar Huluan Subdistrict Simalungun Regency through the use of pellet complete feed based on palm oil fronds and agricultural waste. This activity is conducted on cattle ranchers who are members of the farming community group Huta Gondang Rejo. Farmers are given counseling and training on the processing of palm oil fronds and agricultural waste into livestock feed and the establishment of a complete ration of palm-based pellet and agricultural waste. To facilitate the transfer of this technology to the breeder, then prepared a complete feed pellet with 5 types of machines. Palm Crusher Counter Machines or Palm Crafter Engines with a capacity of 600 kg/hour. Pellet printing machine (granulator) with capacity of 100 kg/hour. Mixer machine (mixer feed) with a capacity of 50 kg/stir. Dryer (Oven) with capacity of 10 kg/rack. Manual press feed press tool with specification 2 kg/print. Measuring the success of this activity is seen from the level of farmer adoption of pelleting technology and the difference of ration conversion between cattle that get complete feed and conventional or traditional. Performance of palm cropping machine for cattle that get complete pellet feed is better than cattle that get conventional or traditional feed. This Chopper machine can count the palm stem from the tip of the base of the leaf to the stem (80% of the palm stem). Through the activities of plant waste feed technology is expected to achieve some outcomes, namely, improve the productivity of farming through the system integration of livestock combine farming system with synergistic system to form an effective, efficient and environmentally friendly.