Rational conjugacy classes of Frobenius stable tori (in a finite group of Lie type) are in bijection with Frobenius-conjugacy classes of the corresponding Weyl group.When the group is the Symplectic group Sp$(2n)$ then the Frobenius action on the Weyl group is trivial and classes of rational tori...

Let $\kappa$ be regular and $\lambda\geq\kappa$. For $f, g\in\kappa^\lambda$ say that $f\le^* g$ if the set $\{\gamma<\lambda:f(\gamma)>g(\gamma)\}$ has size less than $\kappa$. Set $\mathfrak{b}_\kappa^\lambda:=\min\{|F|:F\subseteq \kappa^\lambda\text{ and }\neg\exists y\in \kappa^\lambda\fora...

Looking through meta-MO I have found a proposal of Martin Sleziak to create a new "small-uncountable-cardinals", which I liked since many of my (and not only my) questions fall under this tag. So, I created a new tag "small-uncountable-cardinal" and tagged several my question with this new tag ti...