reserve a,b,c,d,x,y,w,z,x1,x2,x3,x4 , X for set;
reserve A for non empty set;
reserve i,j,k for Element of NAT;
reserve a,b,c,d for Real;
reserve y,r,s,x,t,w for Element of RAT+;
reserve z,z1,z2,z3,z4 for Quaternion;
 reserve x for Real;

theorem
  |.1q.| = 1
proof
A1: Rea 1q =jj by Lm10,Th16;
A2: Im1 1q = zz by Lm10,Th16;
  Im2 1q = zz by Lm10,Th16;
  hence thesis by A1,A2,Lm10,Th16,SQUARE_1:18;
end;
