Reasonable set
= Reasonable set
A set $x$ is reasonable when every member of $\operatorname{TC}(\{x\})$ is countable. In ZFC this is equivalent to $x$ being <hereditarily countable set>[hereditarily countable].
= Reasonable set
A set $x$ is reasonable when every member of $\operatorname{TC}(\{x\})$ is countable. In ZFC this is equivalent to $x$ being <hereditarily countable set>[hereditarily countable].