Discrete time phased Petri box calculus dtphPBC
2026-07-27 • Logic in Computer Science
Logic in Computer Science
AI summaryⓘ
The authors introduce discrete time phased Petri box calculus (dtphPBC), which extends a previous model by including phase type distributed delays for actions that can happen either immediately or after some delay. They represent these delays using special matrices related to Markov chains that have one absorbing state, allowing more detailed timing in the model. The authors define rules for how systems evolve over time using labeled transitions, integrating these delay distributions into the system's behavior. Examples are provided to show how the calculus can model combinations of immediate and delayed actions.
Petri box calculusphase type distributiondiscrete time Markov chaintransition probability matrixabsorbing stateoperational semanticslabeled transition systemstochastic processdeterministic delaytimed multiaction
Authors
Igor V. Tarasyuk
Abstract
We propose discrete time phased Petri box calculus (dtphPBC), an extension with phase type distributed multiaction delays of discrete time stochastic and deterministic Petri box calculus (dtsdPBC), previously presented by I.V. Tarasyuk. In dtphPBC, transition probability matrices (TPMs) of finite absorbing discrete time Markov chains (DTMCs) with a single absorbing state specify discrete phase type (DPH) distributed delays (including zero delay) of the phased multiactions that generalize stochastic and deterministic multiactions from dtsdPBC. The positively phased (timed) multiactions have positive DPH delays represented by the non-empty TPM matrices over transient states (transient TPMs). The zero phased (immediate) multiactions have zero DPH delay represented by the empty transient TPM. The step operational semantics of dtphPBC is constructed via labeled probabilistic transition systems. The transition systems incorporate the absorbing DTMCs of the DPH delays of the executed phased multiactions via the structural operational semantics (SOS) rules. The SOS rules define a labeling with the empty set on the transitions among transient states of the absorbing DTMC and on the self-loop in the absorbing state of it. The transitions going from the transient states (positive phases) to the absorbing state (zero phase) are labeled with the executions, being the positive phases-superscribed timed multiactions whose (positive) delays are defined by the absorbing DTMC. A series of examples demonstrates how to construct the transition systems of the dynamic expressions, combined from timed and immediate multiactions with different operations of the calculus.