8 papers
Fields whose Multiplicative Groups are Linear Spaces
Yuki Nakata
The purpose of this paper is to study fields whose multiplicative groups admit the structure of linear spaces. We prove that the multiplicative group of a finite field is a linear…
fails to predict the outbreak potential in the presence of natural-boosting immunity
Yukihiko Nakata, Ryosuke Omori
Time varying susceptibility of host at individual level due to waning and boosting immunity is known to induce rich long-term behavior of disease transmission dynamics. Meanwhile,…
Delay-induced blow-up in a planar oscillation model
Alexey Eremin, Emiko Ishiwata, Tetsuya Ishiwata +1
In this paper we study a system of delay differential equations from the viewpoint of a finite time blow-up of the solution. We prove that the system admits a blow-up solution, no…
A periodic solution of period two of a delay differential equation
Yukihiko Nakata
In this paper we prove that the following delay differential equation \[ \frac{d}{dt}x(t)=rx(t)\left(1-\int_{0}^{1}x(t-s)ds\right), \] has a periodic solution of period two for $r>…
Unbounded and blow-up solutions for a delay logistic equation with positive feedback
István Győri, Yukihiko Nakata, Gergely Röst
We study bounded, unbounded and blow-up solutions of a delay logistic equation without assuming the dominance of the instantaneous feedback. It is shown that there can exist an exp…
Global stability of an SIS epidemic model with a finite infectious period
Yukihiko Nakata, Gergely Rost
Assuming a general distribution for the sojourn time in the in- fectious class, we consider an SIS type epidemic model formulated as a scalar integral equation. We prove that the e…
Global dynamics of cell mediated immunity in viral infection models with distributed delays
Yukihiko Nakata
In this paper, we investigate global dynamics for a system of delay differential equations which describes a virus-immune interaction in \textit{vivo}. The model has two distribute…
On a generalization of the global attractivity for a periodically forced Pielou's equation
Keigo Ishihara, Yukihiko Nakata
In this paper, we study the global attractivity for a class of periodic difference equation with delay which has a generalized form of Pielou's difference equation. The global dyna…