human: Given a node-centered hypergraph: <hypergraph>, where nodes represent authors and hyperedges represent groups of authors who co-authored the same paper.

Details of the hypergraph:
Center node: "Online minimization of transition systems (extended abstract)"
  Abstract: We are given a transition system implicitly through a compact representation and wish to perform simultaneously reachability analysis and minimization without constructing first the whole system graph. We present an algorithm for this problem that applies to general systems, provided we have appropriate primitive operations for manipulating blocks of states and we can determine termination; the number of operations needed to construct the minimal reachable graph is quadratic in the size of this graph. We specialize the method to obtain efficient algorithms for extended finite state machines that apply separable affine transformations on the variables.

Connected through hyperedge HE-1 (induced by source paper "An implementation of three algorithms for timing verification based on automata emptiness"):
  with members:
    - "Extending Promela and Spin for Real Time"

Connected through hyperedge HE-2 (induced by source paper "Formal methods for protocol testing: a detailed study"):
  with members:
    - "A protocol test generation procedure"
    - "A reduced test suite for protocol conformance testing"
    - "Test development for communication protocols: towards automation"
    - "Validation-based test sequence generation for networks of extended finite state machines"
    - "Bounded sequence testing from deterministic finite state machines"

Question: Please tell me which research area the center author belongs to. The 4 classes are: Computer science, Mathematics, Engineering, Economics, Psychology, Business. Directly output the class name.

gpt: Mathematics