proper support for "isabelle update -D DIR": avoid accidental exclusion of select_dirs (amending e5dafe9e120f);
section \<open>Comprehensive number theory\<close>
theory Number_Theory
imports
Fib
Residues
Eratosthenes
Mod_Exp
Quadratic_Reciprocity
Pocklington
Prime_Powers
Residue_Primitive_Roots
begin
end