"book-pflow-xyz/chapters/appendix-d-glossary.md" . . . "A mathematical modeling language consisting of places, transitions, arcs, and tokens. Formally, a tuple $(P, T, F, W, \\mathbf{m}_0)$ where $P$ is a set of places, $T$ is a set of transitions, $F \\subseteq (P \\times T) \\cup (T \\times P)$ is the flow relation, $W: F \\to \\mathbb{N}$ is the weight function, and $\\mathbf{m}_0$ is the initial marking."@en . . "Petri net"@en .