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: "degrees of freedom region for the mimo x channel"
  Abstract: We provide achievability as well as converse results for the degrees of freedom region of a MIMO $X$ channel, i.e., a system with two transmitters, two receivers, each equipped with multiple antennas, where independent messages need to be conveyed over fixed channels from each transmitter to each receiver. With M=1 antennas at each node, we find that the total (sum rate) degrees of freedom are bounded above and below as $1 \leq\eta_X^\star \leq {4/3}$. If $M>1$ and channel matrices are non-degenerate then the precise degrees of freedom $\eta_X^\star = {4/3}M$. Simple zero forcing without dirty paper encoding or successive decoding, suffices to achieve the ${4/3}M$ degrees of freedom. With equal number of antennas at all nodes, we explore the increase in degrees of freedom when some of the messages are made available to a transmitter or receiver in the manner of cognitive radio. With a cognitive transmitter we show that the number of degrees of freedom $\eta = {3/2}M$ (for $M>1$) on the MIMO $X$ channel. The same degrees of freedom are obtained on the MIMO $X$ channel with a cognitive receiver as well. In contrast to the $X$ channel result, we show that for the MIMO \emph{interference} channel, the degrees of freedom are not increased even if both the transmitter and the receiver of one user know the other user's message. However, the interference channel can achieve the full $2M$ degrees of freedom if \emph{each} user has either a cognitive transmitter or a cognitive receiver. Lastly, if the channels vary with time/frequency then the $X$ channel with single antennas $(M=1)$ at all nodes has exactly 4/3 degrees of freedom with no shared messages and exactly 3/2 degrees of freedom with a cognitive transmitter or a cognitive receiver.

Connected through hyperedge HE-1 (induced by source paper "interference aligned space time transmission with diversity for the 2 times 2 x network"):
  with members:
    - "interference alignment with diversity for the 2 times 2 x network with four antennas"
    - "maximum rate transmission with improved diversity gain for interference networks"
    - "on precoding for constant k user mimo gaussian interference channel with finite constellation inputs"

Connected through hyperedge HE-2 (induced by source paper "generalized signal alignment for arbitrary mimo two way relay channels"):
  with members:
    - "generalized signal alignment for mimo two way x relay channels"
    - "mimo multiway relaying with pairwise data exchange a degrees of freedom perspective"
    - "approximate sum capacity of the y channel"
    - "degrees of freedom for the mimo multi way relay channel"
    - "degrees of freedom for mimo two way x relay channel"
    - "divide and conquer approaching the capacity of the two pair bidirectional gaussian relay network"

Connected through hyperedge HE-3 (induced by source paper "generalized area spectral efficiency an effective performance metric for green wireless communications"):
  with members:
    - "capacity analysis of a multi cell multi antenna cooperative cellular network with co channel interference"
    - "on peak versus average interference power constraints for protecting primary users in cognitive radio networks"

Connected through hyperedge HE-4 (induced by source paper "topological interference management with alternating connectivity"):
  with members:
    - "capacity results for binary fading interference channels with delayed csit"
    - "topological interference management through index coding"
    - "interference networks with no csit impact of topology"
    - "index coding an interference alignment perspective"
    - "elements of cellular blind interference alignment aligned frequency reuse wireless index coding and interference diversity"
    - "on the synergistic benefits of alternating csit for the miso bc"
    - "the ergodic capacity of phase fading interference networks"
    - "on the degrees of freedom of the compound mimo broadcast channels with finite states"

Connected through hyperedge HE-5 (induced by source paper "interactive interference alignment"):
  with members:
    - "real interference alignment exploiting the potential of single antenna systems"
    - "the approximate sum capacity of the symmetric gaussian k user interference channel"
    - "on the degrees of freedom achievable through interference alignment in a mimo interference channel"
    - "feedback interference alignment exact alignment for three users in two time slots"
    - "experiment driven characterization of full duplex wireless systems"
    - "settling the feasibility of interference alignment for the mimo interference channel the symmetric square case"
    - "interference alignment from degrees of freedom to constant gap capacity approximations"
    - "interference channels with source cooperation"

Connected through hyperedge HE-6 (induced by source paper "degrees of freedom of mimo x networks spatial scale invariance one sided decomposability and linear feasibility"):
  with members:
    - "real interference alignment exploiting the potential of single antenna systems"
    - "multiple antenna interference network with receive antenna joint processing and real interference alignment"
    - "on the degrees of freedom achievable through interference alignment in a mimo interference channel"
    - "subspace alignment chains and the degrees of freedom of the three user mimo interference channel"
    - "settling the feasibility of interference alignment for the mimo interference channel the symmetric square case"
    - "degrees of freedom region for an interference network with general message demands"
    - "interference alignment for the k user mimo interference channel"
    - "on feasibility of interference alignment in mimo interference networks"

Connected through hyperedge HE-7 (induced by source paper "diophantine approach to blind interference alignment of homogeneous k user 2x1 miso broadcast channels"):
  with members:
    - "real interference alignment exploiting the potential of single antenna systems"
    - "on the degrees of freedom of k user siso interference and x channels with delayed csit"
    - "optimal use of current and outdated channel state information degrees of freedom of the miso bc with mixed csit"
    - "elements of cellular blind interference alignment aligned frequency reuse wireless index coding and interference diversity"
    - "completely stale transmitter channel state information is still very useful"
    - "on feasibility of interference alignment in mimo interference networks"
    - "on feasibility of interference alignment in mimo interference networks"

Connected through hyperedge HE-8 (induced by source paper "the dof of the k user interference channel with a cognitive relay"):
  with members:
    - "the capacity of the interference channel with a cognitive relay in very strong interference"
    - "capacity to within 3 bits for a class of gaussian interference channels with a cognitive relay"
    - "outer bounds for the interference channel with a cognitive relay"
    - "approaching the capacity of wireless networks through distributed interference alignment"
    - "interference alignment and the degrees of freedom for the k user interference channel"

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)