Electronic Journal of Differential Equations, Vol. 2024 (2024), No. 66, pp. 1-13. Title: Cauchy problem for the Lane-Emden heat flow with sign-changing initial data Authors: Rui Huang (South China Normal Univ., Guangzhou, China) Shanming Ji (South China Univ. of Tech., Guangzhou, China) Yansheng Ma (Northeast Normal Univ., Changchun, China) Abstract: This article concerns the blow-up phenomenon of sign-changing solutions to the Lane-Emden heat flow. We construct sign-changing weak sub-solutions and localization of the positive and negative parts of the sign-changing solutions. We also extend the results to a nonlinear and finite diffusion equations. Submitted August 22, 2024. Published October 29, 2024. Math Subject Classifications: 35K57, 35B40, 35B44, 35K20. Key Words: Lane-Emden heat flow; sign-changing solution; blow-up