human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "on cyclically interval edge colorings of trees"
  Abstract: Abstract. For an undirected, simple, ﬁnite, connected graph G, we denote by V ( )and E(G) the sets of its vertices and edges, respectively. A function ϕ : E(G) →{1,2,...,t} is called a proper edge t-coloring of a graph G if adjacent edges arecolored diﬀerently and each of t colors is used. An arbitrary nonempty subset ofconsecutive integers is called an interval. If ϕ is a proper edge t-coloring of a graphG and x ∈ V (G), then S G (x,ϕ) denotes the set of colors of edges of G which areincident with x. A proper edge t-coloring ϕ of a graph G is called a cyclically-intervalt-coloring if for any x ∈ V(G) at least one of the following two conditions holds: a)S G (x,ϕ) is an interval, b) {1,2,...,t}\S G (x,ϕ) is an interval. For any t ∈ N, let M t be the set of graphs for which there exists a cyclically-interval t-coloring, and letM≡[ t≥1 M t .For an arbitrary tree G, it is proved that G ∈ Mand all possible values of t are foundfor which G ∈ M t .Mathematics subject classiﬁcation: 05C05, 05C15.Keywords and phrases: tree, interval edge coloring, cyclically-interval edge color-ing.

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.DM(Discrete Mathematics)