24 citations · 111 across the 33 of their papers we have counts for
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Nonintegrability of dynamical systems near degenerate equilibria
Kazuyuki Yagasaki
We prove that general three- or four-dimensional systems %of differential equations are real-analytically nonintegrable near degenerate equilibria in the Bogoyavlenskij sense under…
Nonintegrability of time-periodic perturbations of single-degree-of-freedom Hamiltonian systems near homo- and heteroclinic orbits
Kazuyuki Yagasaki
We consider time-periodic perturbations of single-degree-of-freedom Hamiltonian systems and study their real-meromorphic nonintegrability in the Bogoyavlenskij sense using a genera…
Nonintegrability of the SEIR epidemic model
Kazuyuki Yagasaki
We prove the nonintegrability of the susceptible-exposed-infected-removed (SEIR) epidemic model in the Bogoyavlenskij sense. This property of the SEIR model is different from the m…
Nonintegrability of Forced Nonlinear Oscillators
Shoya Motonaga, Kazuyuki Yagasaki
In recent papers by the authors (S.~Motonaga and K.~Yagasaki, Obstructions to integrability of nearly integrable dynamical systems near regular level sets, submitted for publicatio…