RT Journal Article T1 A hierarchy in the family of real surjective functions A1 Fenoy Muñoz, María Del Mar A1 Gámez Merino, José Luis A1 Muñoz Fernández, Gustavo Adolfo A1 Sáez Maestro, Eva AB This expository paper focuses on the study of extreme surjective functions in ℝℝ. We present several different types of extreme surjectivity by providing examples and crucial properties. These examples help us to establish a hierarchy within the different classes of surjectivity we deal with. The classes presented here are: everywhere surjective functions, strongly everywhere surjective functions, κ-everywhere surjective functions, perfectly everywhere surjective functions and Jones functions. The algebraic structure of the sets of surjective functions we show here is studied using the concept of lineability. In the final sections of this work we also reveal unexpected connections between the different degrees of extreme surjectivity given above and other interesting sets of functions such as the space of additive mappings, the class of mappings with a dense graph, the class of Darboux functions and the class of Sierpiński-Zygmund functions in ℝℝ. PB De Gruyter Open Ltd SN 23915455 YR 2017 FD 2017 LK https://hdl.handle.net/20.500.14352/17867 UL https://hdl.handle.net/20.500.14352/17867 LA eng NO Ministerio de Educación, Formación Profesional y Deportes (España) DS Docta Complutense RD 8 abr 2025