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: "bitcoin vs bitcoin cash coexistence or downfall of bitcoin cash"
  Abstract: In Aug. 2017, Bitcoin was split into the original Bitcoin (BTC) and Bitcoin Cash (BCH). Since then, miners have had a choice between BTC and BCH mining because they have compatible proof-of-work algorithms. Therefore, they can freely choose which coin to mine for higher profit, where the profitability depends on both the coin price and mining difficulty. Some miners can immediately switch the coin to mine only when mining difficulty changes because the difficulty changes are more predictable than that for the coin price, and we call this behavior fickle mining. #R##N#In this paper, we study the effects of fickle mining by modeling a game between two coins. To do this, we consider both fickle miners and some factions (e.g., BITMAIN for BCH mining) that stick to mining one coin to maintain that chain. In this model, we show that fickle mining leads to a Nash equilibrium in which only a faction sticking to its coin mining remains as a loyal miner to the less valued coin (e.g., BCH), where loyal miners refer to those who conduct mining even after coin mining difficulty increases. This situation would cause severe centralization, weakening the security of the coin system. #R##N#To determine which equilibrium the competing coin systems (e.g., BTC vs. BCH) are moving toward, we traced the historical changes of mining power for BTC and BCH. In addition, we analyze the recent "hash war" between Bitcoin ABC and SV, which confirms our theoretical analysis. Finally, we note that our results can be applied to any competing cryptocurrency systems in which the same hardware (e.g., ASICs or GPUs) can be used for mining. Therefore, our study brings new and important angles in competitive coin markets: a coin can intentionally weaken the security and decentralization level of the other rival coin when mining hardware is shared between them, allowing for automatic mining.

Connected through hyperedge HE-1 (induced by source paper "bdos blockchain denial of service"):
  with members:
    - "competing semi selfish miners in bitcoin"
    - "sok transparent dishonesty front running attacks on blockchain"
    - "selfish mining in ethereum"
    - "just enough security reducing proof of work ecological footprint"
    - "mind the mining"
    - "cryptocurrency egalitarianism a quantitative approach"
    - "flash boys 2 0 frontrunning transaction reordering and consensus instability in decentralized exchanges"
    - "a deep dive into blockchain selfish mining"

Connected through hyperedge HE-2 (induced by source paper "impossibility of full decentralization in permissionless blockchains"):
  with members:
    - "is stellar as secure as you think"
    - "decentralization in bitcoin and ethereum networks"
    - "reward sharing schemes for stake pools"
    - "the gap game"
    - "be selfish and avoid dilemmas fork after withholding faw attacks on bitcoin"
    - "hijacking bitcoin routing attacks on cryptocurrencies"
    - "the miner s dilemma"
    - "majority is not enough bitcoin mining is vulnerable"

Connected through hyperedge HE-3 (induced by source paper "an eye for an eye economics of retaliation in mining pools"):
  with members:
    - "the gap game"
    - "be selfish and avoid dilemmas fork after withholding faw attacks on bitcoin"
    - "optimal selfish mining strategies in bitcoin"
    - "on subversive miner strategies and block withholding attack in bitcoin digital currency"
    - "the miner s dilemma"
    - "majority is not enough bitcoin mining is vulnerable"
    - "analysis of bitcoin pooled mining reward systems"

Connected through hyperedge HE-4 (induced by source paper "bonded mining difficulty adjustment by miner commitment"):
  with members:
    - "bobtail a proof of work target that minimizes blockchain mining variance draft"
    - "estimation of miner hash rates and consensus on blockchains draft"
    - "enhancing bitcoin security and performance with strong consistency via collective signing"
    - "bitcoin meets strong consistency"
    - "cryptocurrencies without proof of work"
    - "majority is not enough bitcoin mining is vulnerable"

Connected through hyperedge HE-5 (induced by source paper "greedy but cautious conditions for miner convergence to resource allocation equilibrium"):
  with members:
    - "diversification across mining pools optimal mining strategies under pow"
    - "game of coins"
    - "using economic risk to model miner hash rate allocation in cryptocurrencies"
    - "optimal selfish mining strategies in bitcoin"
    - "majority is not enough bitcoin mining is vulnerable"

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.CR(Cryptography and Security)