Gamma is a kernel language in which programs are described in terms of multiset transformations following the chemical reaction metaphor. Previous work has demonstrated its signiicance for the construction of massively parallel programs but also highlighted some limitations. We introduce a higher-order extension of this formalism unifying the program and data syntactic categories. As a conseque...

This Isabelle/HOL formalization introduces a nested multiset datatype and de nes Dershowitz and Manna's nested multiset order. The order is proved well founded and linear. By removing one constructor, we transform the nested multisets into hereditary multisets. These are isomorphic to the syntactic ordinals the ordinals can be recursively expressed in Cantor normal form. Addition, subtraction, ...

We compare the expressive power of a class of well-structured transition systems that includes relational automata, Petri nets, lossy channel systems, and constrained multiset rewriting systems. For each one of these models we study the class of languages generated by labelled transition systems describing their semantics. We consider here two types of accepting conditions: coverability and rea...

We investigate model checking of a computation model called Constrained Multiset Rewriting Systems (CMRS). A CMRS operates on configurations which are multisets of monadic predicate symbols, each with an argument ranging over the natural numbers. The transition relation is defined by a finite set of rewriting rules which are conditioned by simple inequalities on variables and constants. This mo...

Given a graph G, a dominating set D is a set of vertices such that any vertex in G has at least one neighbor (or possibly itself) in D. A {k}-dominating multiset Dk is a multiset of vertices such that any vertex in G has at least k vertices from its closed neighborhood in Dk when counted with multiplicity. In this paper, we utilize the approach developed by Clark and Suen (2000) and properties ...

Whether P systems with only one catalyst can already be computationally complete, is still an open problem. Here we establish computational completeness by using specific variants of additional control mechanisms. At each step using only multiset rewriting rules from one set of a finite number of sets of multiset rewriting rules allows for obtaining computational completeness with one catalyst ...

Formal analysis of security protocols is largely based on a set of assumptions commonly referred to as the Dolev-Yao model. Two formalisms that state the basic assumptions of this model are related here: strand spaces [6] and multiset rewriting with existential quantification [2, 5]. Although it is fairly intuitive that these two languages should be equivalent in some way, a number of modificat...

Scheduling The problem of all optimizations is to decide if their modifications to the reservation vector are valid or not. I.e. if the constrains for scheduling instructions remain exactly the same before and after the (possibly illegal) optimization. The problem can be solved by converting the reservation vector back into the unambiguous set of relevant issue-multisets. If – after modifying t...