There is already a question about the name of such a set: Name for numbers expressible as radicals
My question is related.
The rational complex numbers might be denoted ℚ(i), and the algebraic numbers are denoted . Between these two sets is that of radical expressions (the closure of the integers under arithmetic and radicals). Is there a conventional symbol for this set?
As an aside, are there any recommended references on the subject of radical expressions?
There is no conventional symbol for the set of radical expressions.
If you find yourself needing one, just define one and be explicit about it.