Sergiu Ivanov

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SymPy is an open source computer algebra system written in pure Python. It 9 is built with a focus on extensibility and ease of use, through both interactive and programmatic 10 applications. These characteristics have led SymPy to become the standard symbolic library for 11 the scientific Python ecosystem. This paper presents the architecture of SymPy, a(More)
We consider the (one-dimensional) array counterpart of contextual as well as insertion and deletion string grammars and consider the operations of array insertion and deletion in array grammars. First we show that the emptiness problem for P systems with (one-dimensional) insertion rules is undecidable. Then we show computational completeness of P systems(More)
Let d ∈ N; then a d-dimensional array A over an alphabet V is a function A : Z → V ∪ {#}, where shape (A) = { v ∈ Z | A (v) 6= # } is finite and # / ∈ V is called the background or blank symbol. The set of all d-dimensional arrays over V is denoted by V ∗d. For v ∈ Z, v = (v1, . . . , vd), the norm of v is ‖v‖ = max {|vi| | 1 ≤ i ≤ d}. The translation τv :(More)
The focus of this paper is the family of languages generated by transitional non-cooperative P systems without further ingredients. This family can also be defined by so-called time yields of derivation trees of context-free grammars. In this paper we prove that such languages can be parsed in polynomial time, where the degree of polynomial may depend on(More)
1 Institute of Mathematics and Computer Science Academy of Sciences of Moldova Academiei 5, Chişinău MD-2028 Moldova E-mail: {sivanov,artiom} 2 Technical University of Moldova, Faculty of Computers, Informatics and Microelectronics, Ştefan cel Mare 168, Chişinău MD-2004 Moldova 3 Università degli Studi di Milano-Bicocca Dipartimento di Informatica,(More)