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 achievable degrees of freedom for mimo x channels"
  Abstract: In this paper, the achievable DoF of MIMO X channels for constant channel coefficients with $M_t$ antennas at transmitter $t$ and $N_r$ antennas at receiver $r$ ($t,r=1,2$) is studied. A spatial interference alignment and cancelation scheme is proposed to achieve the maximum DoF of the MIMO X channels. The scenario of $M_1\geq M_2\geq N_1\geq N_2$ is first considered and divided into 3 cases, $3N_2 N_1$, otherwise it is 1/2 or 1 less than the outer-bound; in Case $C$, the achievable DoF is equal to the outer-bound $2/3(M_1+M_2)$ if $(3N_2-M_1-M_2)\mod 3=0$, and it is 1/3 or 1/6 less than the outer-bound if $(3N_2-M_1-M_2)\mod 3=1 \mathrm{or} 2$. In the scenario of $M_t\leq N_r$, the exact symmetrical results of DoF can be obtained.

Connected through hyperedge HE-1 (induced by source paper "secure degrees of freedom of wireless x networks using artificial noise alignment"):
  with members:
    - "secure degrees of freedom of one hop wireless networks"
    - "multiaccess channel with partially cooperating encoders and security constraints"
    - "secure degrees of freedom of k user gaussian interference channels a unified view"
    - "secure degrees of freedom of mimo x channels with output feedback and delayed csit"
    - "on x channels with feedback and delayed csi"
    - "secure communication over parallel relay channel"
    - "interference alignment for secrecy"
    - "interference assisted secret communication"

Connected through hyperedge HE-2 (induced by source paper "on cooperative multiple access channels with delayed csi at transmitters"):
  with members:
    - "capacity results for binary fading interference channels with delayed csit"
    - "multiple access channels with states causally known at transmitters"
    - "secure degrees of freedom of mimo x channels with output feedback and delayed csit"
    - "estimation with a helper who knows the interference"
    - "wyner ziv type versus noisy network coding for a state dependent mac"
    - "wireless network information flow a deterministic approach"
    - "the state dependent semideterministic broadcast channel"
    - "bounds on the capacity of the relay channel with noncausal state at source"

Connected through hyperedge HE-3 (induced by source paper "secure degrees of freedom of mimo x channels with output feedback and delayed csit"):
  with members:
    - "on the degrees of freedom of k user siso interference and x channels with delayed csit"
    - "degrees of freedom region of the mimo interference channel with output feedback and delayed csit"
    - "topological interference management with alternating connectivity"
    - "multiaccess channel with partially cooperating encoders and security constraints"
    - "new results on multiple input multiple output broadcast channels with confidential messages"
    - "on x channels with feedback and delayed csi"
    - "secure communication over parallel relay channel"
    - "index coding an interference alignment perspective"

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.IT(Information Theory)