Abstract We show that the class of functions that are perfectly everywhere surjective and almost continuous in the sense of Stallings but are not Jones functions is c + -lineable.… Click to show full abstract
Abstract We show that the class of functions that are perfectly everywhere surjective and almost continuous in the sense of Stallings but are not Jones functions is c + -lineable. Moreover, it is consistent that this class is 2 c -lineable, as this holds when 2 c = c . We also prove that the additivity number for this class is between ω 1 and c . This lower bound can be achieved even when ω 1 c , as it is implied by the Covering Property Axiom CPA. The main step in this proof is the following theorem, which is of independent interest: CPA implies that there exists a family F ⊂ C ( R ) of cardinality ω 1 c such that for every g ∈ C ( R ) the set g ∖ ⋃ F has cardinality less than c . Some open problems are posed as well.
               
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