Electronic Journal of Differential Equations, Vol. 2025 (2025), No. 81, pp. 1-10. Title: Finite-time blow-up in a quasilinear fully parabolic attraction-repulsion chemotaxis system with density-dependent sensitivity Authors: Yutaro Chiyo (Tokyo Univ. of Science, Tokyo, Japan) Takeshi Uemura (Tokyo Univ. of Science, Tokyo, Japan) Tomomi Yokota (Tokyo Univ. of Science, Tokyo, Japan) Abstract: This article concerns the quasilinear fully parabolic attraction-repulsion chemotaxis system $$\displaylines{ u_t=\nabla \cdot ((u+1)^{m-1}\nabla u -\chi u(u+1)^{p-2} \nabla v + \xi u(u+1)^{p-2}\nabla w),\quad x \in \Omega,\; t>0,\cr v_t=\Delta v+\alpha u-\beta v, \quad x \in \Omega,\; t>0,\cr w_t=\Delta w+\gamma u-\delta w, \quad x \in \Omega,\; t>0 }$$ with homogeneous Neumann boundary conditions, where $\Omega \subset \mathbb{R}^n$ $(n \in \{2,3\})$ is an open ball, $m, p \in \mathbb{R}$, $\chi, \xi, \alpha, \beta, \gamma, \delta >0$ are constants. The main result asserts finite-time blow-up of solutions to this system with some positive initial data when $\chi\alpha-\xi\gamma>0$, $p \ge 2$ and $p-m >2/n$. Submitted May 1, 2025. Published August 06, 2025. Math Subject Classifications: 35B44, 35K59, 35Q92, 92C17. Key Words: Finite-time blow-up; quasilinear; attraction-repulsion; chemotaxis.