Improvements and generalizations of results concerning attraction-repulsion chemotaxis models

We enter the details of two recent articles concerning as many chemotaxis models, one nonlinear and the other linear, and both with produced chemoattractant and saturated chemorepellent. More precisely, we are referring respectively to the papers “Boundedness in a nonlinear attraction-repulsion Keller–Segel system with production and consumption,” by S. Frassu, C. van der Mee and G. Viglialoro [J. Math. Anal. Appl. 504(2):125428, 2021] and “Boundedness in a chemotaxis system with consumed chemoattractant and produced chemorepellent,” by S. Frassu and G. Viglialoro [Nonlinear Anal. 213:112505, 2021]. These works, when properly analyzed, leave open room for some improvement of their results. We generalize the outcomes of the mentioned articles, establish other statements, and put all the claims together; in particular, we select the sharpest ones and schematize them. Moreover, we complement our research also when logistic sources are considered in the overall study.