vector_addition_system (923B)
1 # Vector addition system (VAS) 2 3 Also called "vector addition system with states" (VASS) 4 5 - Like a [word_automaton] but with a configuration featuring a vector 6 - Transitions add a vector to the current vector 7 - They can only be taken if every coordinate remains positive 8 9 [ginzburg1980vector]: determine when a VAS defines a [regular_language] 10 11 Generalizations: 12 - [vector_addition_tree_automata] 13 - [vector_addition_system_pushdown] 14 - [vector_addition_system_nested] 15 16 Complexity of the [reachability] problem: [ackermann_function] 17 - https://www.quantamagazine.org/an-easy-sounding-problem-yields-numbers-too-big-for-our-universe-20231204/ 18 - apparently still open when [dimension] is constant 19 20 two-dimensional VAS with one test on counters, like [counter_automata]: [leroux2020reachability] 21 22 Restrictions: 23 24 - [1_VASS], with only one counter 25 - see also [one_conter_automata] 26 27 Up: [automata] 28 29 See also: [counter_automata]