General criteria for a strong notion of lineability

Abstract

A subset $A$ of a vector space $X$ is called $\alpha$-lineable whenever $A$ contains, except for the null vector, a subspace of dimension $\alpha$. If $X$ has a topology, then $A$ is $\alpha$-spaceable if such subspace can be chosen to be closed. The vast existing literature on these topics has shown that positive results for lineability and spaceability are quite common. Recently, the stricter notions of $\left( \alpha,\beta\right) $% -lineability/spaceability were introduced as an attempt to shed light to more subtle issues. In this paper, among other results, we prove some general criteria for the notion of $\left( \alpha,\beta\right) $-spaceability and, as applications, we extend recent results of different authors.