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: "containment for conditional tree patterns"
  Abstract: A Conditional Tree Pattern (CTP) expands an XML tree pattern with labels#N#attached to the descendant edges. These labels can be XML element names or#N#Boolean CTPs. The meaning of a descendant edge labelled by A and ending in a#N#node labelled by B is a path of child steps ending in a B node such that all#N#intermediate nodes are A nodes. In effect this expresses the until B, A holds#N#construction from temporal logic.This paper studies the containment problem for#N#CTP. For tree patterns (TP), this problem is known to be coNP-complete. We show#N#that it is PSPACE-complete for CTP. This increase in complexity is due to the#N#fact that CTP is expressive enough to encode an unrestricted form of label#N#negation: ${*}\setminus a$, meaning "any node except an a-node". Containment of#N#TP expanded with this type of negation is already PSPACE-hard. CTP is a#N#positive, forward, first order fragment of Regular XPath. Unlike TP, CTP#N#expanded with disjunction is not equivalent to unions of CTP's. Like TP, CTP is#N#a natural fragment to consider: CTP is closed under intersections and CTP with#N#disjunction is equally expressive as positive existential first order logic#N#expanded with the until operator.

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.LO(Logic in Computer Science)