36 citations · 59 across the 17 of their papers we have counts for
18 papers
Immune history shapes recurrent epidemics of antigenically related variants
Ryuichi Kumata, Yuma Fujimoto, Hisashi Ohtsuki +1
Population immunity carried over from past epidemics of an antigenically variable pathogen influences the epidemic of new variants based on their antigenic similarity to the previo…
Linear Convergence in Games with Delayed Feedback via Extra Prediction
Yuma Fujimoto, Kenshi Abe, Kaito Ariu
Feedback delays are inevitable in real-world multi-agent learning. They are known to severely degrade performance, and the convergence rate under delayed feedback is still unclear,…
Learning from Delayed Feedback in Games via Extra Prediction
Yuma Fujimoto, Kenshi Abe, Kaito Ariu
This study raises and addresses the problem of time-delayed feedback in learning in games. Because learning in games assumes that multiple agents independently learn their strategi…
Hamiltonian of polymatrix zero-sum games
Toshihiro Ota, Yuma Fujimoto
The understanding of a dynamical system's properties can be significantly advanced by establishing it as a Hamiltonian system and then systematically exploring its inherent symmetr…
Time-Varyingness in Auction Breaks Revenue Equivalence
Yuma Fujimoto, Kaito Ariu, Kenshi Abe
Auction is applied for trade with various mechanisms. A simple but practical question is which mechanism, typically first-price or second-price auctions, is preferred from the pers…
Synchronization in Learning in Periodic Zero-Sum Games Triggers Divergence from Nash Equilibrium
Yuma Fujimoto, Kaito Ariu, Kenshi Abe
Learning in zero-sum games studies a situation where multiple agents competitively learn their strategy. In such multi-agent learning, we often see that the strategies cycle around…
Global Behavior of Learning Dynamics in Zero-Sum Games with Memory Asymmetry
Yuma Fujimoto, Kaito Ariu, Kenshi Abe
This study examines the global behavior of dynamics in learning in games between two players, X and Y. We consider the simplest situation for memory asymmetry between two players:…
Nash Equilibrium and Learning Dynamics in Three-Player Matching -Action Games
Yuma Fujimoto, Kaito Ariu, Kenshi Abe
Learning in games discusses the processes where multiple players learn their optimal strategies through the repetition of game plays. The dynamics of learning between two players i…
Evolutionary stability of cooperation by the leading eight norms in indirect reciprocity under noisy and private assessment
Yuma Fujimoto, Hisashi Ohtsuki
Indirect reciprocity is a mechanism that explains large-scale cooperation in human societies. In indirect reciprocity, an individual chooses whether or not to cooperate with anothe…
Memory Asymmetry Creates Heteroclinic Orbits to Nash Equilibrium in Learning in Zero-Sum Games
Yuma Fujimoto, Kaito Ariu, Kenshi Abe
Learning in games considers how multiple agents maximize their own rewards through repeated games. Memory, an ability that an agent changes his/her action depending on the history…
Evolutionary stability of cooperation in indirect reciprocity under noisy and private assessment
Yuma Fujimoto, Hisashi Ohtsuki
Indirect reciprocity is a mechanism that explains large-scale cooperation in humans. In indirect reciprocity, individuals use reputations to choose whether or not to cooperate with…
Learning in Multi-Memory Games Triggers Complex Dynamics Diverging from Nash Equilibrium
Yuma Fujimoto, Kaito Ariu, Kenshi Abe
Repeated games consider a situation where multiple agents are motivated by their independent rewards throughout learning. In general, the dynamics of their learning become complex.…
Reputation structure in indirect reciprocity under noisy and private assessment
Yuma Fujimoto, Hisashi Ohtsuki
Evaluation relationships are pivotal for maintaining a cooperative society. A formation of the evaluation relationships has been discussed in terms of indirect reciprocity, by mode…
Game-theoretical approach to minimum entropy productions in information thermodynamics
Yuma Fujimoto, Sosuke Ito
In a situation where each player has control over the transition probabilities of each subsystem, we game-theoretically analyze the optimization problem of minimizing both the part…
Exploitation by asymmetry of information reference in coevolutionary learning in prisoner's dilemma game
Yuma Fujimoto, Kunihiko Kaneko
Mutual relationships, such as cooperation and exploitation, are the basis of human and other biological societies. The foundations of these relationships are rooted in the decision…
Emergence of Exploitation as Symmetry Breaking in Iterated Prisoner's Dilemma
Yuma Fujimoto, Kunihiko Kaneko
In society, mutual cooperation, defection, and asymmetric exploitative relationships are common. Whereas cooperation and defection are studied extensively in the literature on game…
Functional Dynamics by Intention Recognition in Iterated Games
Yuma Fujimoto, Kunihiko Kaneko
Intention recognition is an important characteristic of intelligent agents. In their interactions with others, they try to read others' intentions and make an image of others to ch…
Hierarchical Prisoner's Dilemma in Hierarchical Public-Goods Game
Yuma Fujimoto, Takahiro Sagawa, Kunihiko Kaneko
The dilemma in cooperation is one of the major concerns in game theory. In a public-goods game, each individual pays a cost for cooperation, or to prevent defection, and receives a…