20XX 


Group theory and generalizations 

20Hxx 

Other groups of matrices [See also 15A30] 


20H05 
Unimodular groups, congruence subgroups [See also 11F06, 19B37, 22E40, 51F20] 


20H10 
Fuchsian groups and their generalizations [See also 11F06, 22E40, 30F35, 32Nxx] 


20H15 
Other geometric groups, including crystallographic groups [See also 51XX, especially 51F15, and 82D25] 


20H20 
Other matrix groups over fields 


20H25 
Other matrix groups over rings 


20H30 
Other matrix groups over finite fields 


20H99 
None of the above, but in this section 