@ARTICLE{10.21494/ISTE.OP.2021.0698, 

TITLE={Estimation de l’explosion et de temps d’existence pour l’équation de Tricomi généralisée avec des non-linéarités mixtes}, 
  
AUTHOR={Makram Hamouda, Mohamed Ali Hamza, }, 
	
JOURNAL={Avancées en Mathématiques Pures et Appliquées}, 
	
VOLUME={12}, 

NUMBER={Numéro spécial : AUS-ICMS 2020}, 
	
YEAR={2021}, 

URL={https://openscience.fr/Estimation-de-l-explosion-et-de-temps-d-existence-pour-l-equation-de-Tricomi}, 
	
DOI={10.21494/ISTE.OP.2021.0698}, 
	
ISSN={1869-6090}, 
	
ABSTRACT={We study in this article the blow-up of the solution of the generalized Tricomi equation in the presence of two mixed nonlinearities, namely we consider
$$${(Tr) \hspace{1cm} u_{tt}-t^{2m}\Delta u=}$$$|$$${u_t}$$$|$$${^p+}$$$|$$${u}$$$|$$${^q}$$$,  $$${\quad \mbox{in}\ \mathbb{R}^N\times[0,\infty)}$$$,
with small initial data, where $$${m ≥ 0}$$$.
For the problem $$${(Tr)}$$$ with $$${m = 0}$$$, which corresponds to the uniform wave speed of propagation, it is known that the presence of mixed nonlinearities generates a new blow-up region in comparison with the case of a one nonlinearity (|$$${u_t}$$$|$$${^p}$$$ or |$$${u}$$$|$$${^q}$$$). We show in the present work that the competition between the two nonlinearities still yields a new blow region for the Tricomi equation $$${(Tr)}$$$ with $$${m ≥ 0}$$$, and we derive an estimate of the lifespan in terms of the Tricomi parameter $$${m}$$$. As an application of the method developed for the study of the equation $$${(Tr)}$$$ we obtain with a different approach the same blow-up result as in [18] when we consider only one time-derivative nonlinearity, namely we keep only |$$${u_t}$$$|$$${^p}$$$ in the right-hand side of $$${(Tr)}$$$.}}