"Source: Text/Geometry/GrpPSL2.text";
"Line: 660";
"Date: Tue Jun  7 22:27:14 2016";
"Main: Fri Sep 26 14:29:19 2025";
// original file: Text/Geometry/GrpPSL2.text, line: 660
// Example: H142E6 ()
print "Example: H142E6";
ei := GetEchoInput();
SetEchoInput(true);
// examples of defining matrix elements of congruence subgroups:

G := PSL2(Integers());
G![2,0,0,2];
H := CongruenceSubgroup([2,3,6]);
H![7,6,8,7];                   
SetEchoInput(ei);
