// (504,156) signature (2,3,7) K:=CyclotomicField(7); P6:=ProjectiveSpace(K,6); X:=Scheme(P6,[ x_0^2+x_1^2+x_2^2+x_3^2+x_4^2+x_5^2+x_6^2, x_0^2+z_7*x_1^2+z_7^2*x_2^2+z_7^3*x_3^2+z_7^4*x_4^2+z_7^5*x_5^2+z_7^6*x_6^2, x_0^2+z_7^(-1)*x_1^2+z_7^(-2)*x_2^2+z_7^(-3)*x_3^2+z_7^(-4)*x_4^2+z_7^(-5)*x_5^2+z_7^(-6)*x_6^2, (z_7^(-3)-z_7^3)*x_0*x_6-(z_7^(-2)-z_7^2)*x_1*x_4+(z_7-z_7^(-1))*x_3*x_5, (z_7^(-3)-z_7^3)*x_1*x_0-(z_7^(-2)-z_7^2)*x_2*x_5+(z_7-z_7^(-1))*x_4*x_6, (z_7^(-3)-z_7^3)*x_2*x_1-(z_7^(-2)-z_7^2)*x_3*x_6+(z_7-z_7^(-1))*x_5*x_0, (z_7^(-3)-z_7^3)*x_3*x_2-(z_7^(-2)-z_7^2)*x_4*x_0+(z_7-z_7^(-1))*x_6*x_1, (z_7^(-3)-z_7^3)*x_4*x_3-(z_7^(-2)-z_7^2)*x_5*x_1+(z_7-z_7^(-1))*x_0*x_2, (z_7^(-3)-z_7^3)*x_5*x_4-(z_7^(-2)-z_7^2)*x_6*x_2+(z_7-z_7^(-1))*x_1*x_3, (z_7^(-3)-z_7^3)*x_6*x_5-(z_7^(-2)-z_7^2)*x_0*x_3+(z_7-z_7^(-1))*x_2*x_4 ]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=DiagonalMatrix([1,-1,-1,-1,1,1,-1]); B:=Matrix([ [0, 1/2, 1/2, -1/2, 0, -1/2, 0], [-1/2, -1/2, 1/2, 0, -1/2, 0, 0], [1/2, -1/2, 0, -1/2, 0, 0, -1/2], [-1/2, 0, -1/2, 0, 0, -1/2, -1/2], [0, 1/2, 0, 0, -1/2, 1/2, -1/2], [1/2, 0, 0, 1/2, -1/2, -1/2, 0], [0, 0, 1/2, 1/2, 1/2, 0, -1/2] ]); Order(A); Order(B); Order( (A*B)^-1); GL7K:=GeneralLinearGroup(7,K); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); // (144,127) signature (2,3,12) K:=CyclotomicField(12); z_6:=z_12^2; i:=z_12^3; z_3:=z_12^4; P6:=ProjectiveSpace(K,6); X:=Scheme(P6,[x_0^2 + x_3*x_4 - z_6*x_3*x_5 - z_6*x_5*x_6, 2*i*x_1^2 + x_3*x_4 + z_6*x_3*x_5 + 2*x_4*x_6 - z_6*x_5*x_6, 2*i*x_1*x_2 + (-2*z_6 + 1)*x_3*x_4 + z_6*x_3*x_5 - 2*z_6*x_4*x_6 + z_6*x_5*x_6, 2*i*x_2^2 -x_3*x_4 + (-z_6 + 2)*x_3*x_5 + (2*z_6 - 2)*x_4*x_6 + (-z_6 + 2)*x_5*x_6, x_1*x_3 - z_6*x_2*x_6 + z_12*x_4^2 + (z_12^3 - 2*z_12)*x_4*x_5 + z_12*x_5^2, x_1*x_4 + (-z_6 + 1)*x_2*x_5 -x_3*x_6 - x_6^2, x_1*x_5 - x_2*x_5 + x_3^2 + (-z_6 + 2)*x_3*x_6, x_1*x_6 + x_2*x_6 + -z_12*x_4^2 + z_12*x_4*x_5 - z_12*x_5^2, x_2*x_3 - z_6*x_2*x_6 + z_12*x_4^2, x_2*x_4 + (-z_6 - 1)*x_2*x_5 + z_6*x_3^2 + 2*z_6*x_3*x_6 + z_6*x_6^2 ]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=Matrix([ [-1,0,0,0,0,0,0], [0,z_12^-1,-z_12, 0,0,0,0], [0,-z_12,-z_12^-1,0,0,0,0], [0,0,0,0,z_12^2,z_12^2,0], [0,0,0,-z_3,0,0,z_3], [0,0,0,0,0,0,-z_3], [0,0,0,0,0,z_6,0] ]); B:=Matrix([ [z_3,0,0,0,0,0,0], [0,-1,z_3,0,0,0,0], [0,z_6,0,0,0,0,0], [0,0,0,z_3,0,0,1], [0,0,0,0,z_3,0,0], [0,0,0,0,-z_3,-z_6,0], [0,0,0,0,0,0,1] ]); Order(A); Order(B); Order( (A*B)^-1); GL7K:=GeneralLinearGroup(7,K); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); // (64,41) signature (2,4,16) K:=CyclotomicField(16); z_8:=z_16^2; i:=z_16^4; P6:=ProjectiveSpace(K,6); X:=Scheme(P6,[ x_0^2+x_1*x_2, x_3*x_4-z_8*x_5*x_6, x_1^2+x_3*x_6+i*x_4*x_5, x_2^2+i*x_3*x_6+x_4*x_5, x_0*x_1+z_16^7*x_3^2-z_16^5*x_5^2, x_0*x_2-z_16^7*x_4^2+z_16^5*x_6^2, x_0*x_3-z_16*x_2*x_6, x_0*x_4+z_16*x_1*x_5, x_0*x_5+z_16^7*x_2*x_4, x_0*x_6-z_16^7*x_1*x_3 ]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0], [0, 0, 0, 0, 1, 0, 0], [0, 0, 0, 1, 0, 0, 0], [0, 0, 0, 0, 0, 0, 1], [0, 0, 0, 0, 0, 1, 0] ]); B:=Matrix([ [z_8^2, 0, 0, 0, 0, 0, 0], [0, 0, -z_8, 0, 0, 0, 0], [0, -z_8^3, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 1], [0, 0, 0, 0, 0, -z_8, 0], [0, 0, 0, 0, -z_8^3, 0, 0], [0, 0, 0, 1, 0, 0, 0] ]); Order(A); Order(B); Order( (A*B)^-1); GL7K:=GeneralLinearGroup(7,K); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); // (54,6) signature (2,6,9) K:=CyclotomicField(18); z_9:=z_18^2; z_6:=z_18^3; z_3:=z_18^6; P6:=ProjectiveSpace(K,6); X:=Scheme(P6,[ x_1*x_6 + x_2*x_4 + x_3*x_5, x_0^2-x_1*x_6 +z_6*x_2*x_4 -z_3*x_3*x_5, x_1*x_4 + z_3*x_2*x_5 - z_6*x_3*x_6, x_1*x_5 + z_3*x_2*x_6 - z_6*x_3*x_4, x_0*x_1-z_6*x_5^2-x_4*x_6, x_0*x_2+x_6^2-z_3*x_4*x_5, x_0*x_3+z_3*x_4^2+z_6*x_5*x_6, x_0*x_4-x_1^2+z_3*x_2*x_3, x_0*x_5-z_3*x_2^2-z_6*x_1*x_3, x_0*x_6+z_6*x_3^2+x_1*x_2]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=Matrix([ [-1,0,0,0,0,0,0], [0,0,0,0,0,0,z_9^4], [0,0,0,0,z_9,0,0], [0,0,0,0,0,z_9^7,0], [0,0,z_9^-1,0,0,0,0], [0,0,0,z_9^2,0,0,0], [0,z_9^5,0,0,0,0,0] ]); B:=Matrix([ [z_6,0,0,0,0,0,0], [0,0,0,0,0,z_3,0], [0,0,0,0,0,0,z_3], [0,0,0,0,z_3,0,0], [0,z_3^2,0,0,0,0,0], [0,0,z_3^2,0,0,0,0], [0,0,0,z_3^2,0,0,0] ]); Order(A); Order(B); Order( (A*B)^-1); GL7K:=GeneralLinearGroup(7,K); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); // (54,3) signature (2,6,9) cyclic trigonal K:=CyclotomicField(9); z_3:=z_9^3; P6:=ProjectiveSpace(K,6); X:=Scheme(P6,[ -x_1*x_2+x_0*x_3, -x_1*x_3+x_0*x_4, -x_3^2+x_2*x_4, -x_1*x_4+x_0*x_5, -x_3*x_4+x_2*x_5, -x_4^2+x_3*x_5, -x_1*x_5+x_0*x_6, -x_3*x_5+x_2*x_6, -x_4*x_5+x_3*x_6, -x_5^2+x_4*x_6, x_0^3-x_6^2*x_3+x_2^3, x_0^2*x_1-x_6^2*x_4+x_2^2*x_3, x_0*x_1^2-x_6^2*x_5+x_2^2*x_4, x_1^3-x_6^2*x_6+x_2^2*x_5 ]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=Matrix([ [0,1,0,0,0,0,0], [1,0,0,0,0,0,0], [0,0,0,0,0,0,-1], [0,0,0,0,0,-1,0], [0,0,0,0,-1,0,0], [0,0,0,-1,0,0,0], [0,0,-1,0,0,0,0] ]); B:=Matrix([ [0,z_9^2,0,0,0,0,0], [z_9,0,0,0,0,0,0], [0,0,0,0,0,0,-z_9^5], [0,0,0,0,0,-z_9^4,0], [0,0,0,0,-z_9^3,0,0], [0,0,0,-z_9^2,0,0,0], [0,0,-z_9,0,0,0,0] ]); Order(A); Order(B); Order( (A*B)^-1); GL7K:=GeneralLinearGroup(7,K); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); // (48,32) K:=CyclotomicField(6); z_3:=z_6^2; t:=2*z_6 - 1; P6:=ProjectiveSpace(K,6); X:=Scheme(P6,[ x_0^2+x_3*x_5 + z_6*x_3*x_6 + (-z_6 + 1)*x_4*x_6, t*(x_1*x_3 - x_2*x_4+ x_1*x_5) - x_1*x_6 + x_2*x_5 - x_2*x_6, t*(2*x_1*x_4 - x_2*x_5 + x_2*x_6)+ x_1*x_5 - x_1*x_6, t*(2*x_2*x_3 + x_1*x_6 - x_2*x_5) + 3*x_1*x_5 + x_2*x_6, -3*(x_1^2+x_3*x_5 - x_3*x_6) + t*(x_4*x_5 - x_4*x_6)+2*x_5^2 + 2*(z_6 - 1)*x_5*x_6 -2*z_6*x_6^2, -3*(x_1*x_2 - x_4*x_5)+t*(x_3*x_5 - x_3*x_6 + x_4*x_6-x_5^2) + 2*z_6*x_5*x_6 - x_6^2, -3*(x_2^2-x_3*x_5 - x_4*x_6)+ t*(x_3*x_6 -3*x_4*x_5) +2*(z_6 + 1)*x_5*x_6 + 2*(z_6 - 1)*x_6^2, -3*(2*x_4^2-x_3*x_5 + x_3*x_6) +t*(- x_4*x_5 + x_4*x_6)+2*x_5^2 + 2*(z_6 - 1)*x_5*x_6 - 2*z_6*x_6^2, -3*(-2*x_3*x_4 + x_4*x_5) + t*(- x_3*x_5 + x_3*x_6 - x_4*x_6-x_5^2) + 2*z_6*x_5*x_6 - x_6^2, -3*(2*x_3^2 + x_3*x_5 +x_4*x_6) +t*(- x_3*x_6 + 3*x_4*x_5) +2*(z_6 + 1)*x_5*x_6 + 2*(z_6 - 1)*x_6^2 ]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=Matrix([ [z_3,0,0,0,0,0,0], [0,0,-z_3,0,0,0,0], [0,-z_6,-1,0,0,0,0], [0,0,0,-1,z_6,0,0], [0,0,0,z_3,0,0,0], [0,0,0,0,0,z_3,-z_6], [0,0,0,0,0,0,1] ]); B:=Matrix([ [-1,0,0,0,0,0,0], [0,0,1,0,0,0,0], [0,-1,0,0,0,0,0], [0,0,0,0,-1,0,0], [0,0,0,1,0,0,0], [0,0,0,0,0,z_3,-z_6], [0,0,0,0,0,-z_6,-z_3] ]); Order(A); Order(B); Order( (A*B)^-1); GL7K:=GeneralLinearGroup(7,K); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); // (42,4) signature (2,6,21) cyclic trigonal K:=CyclotomicField(21); z_3:=z_21^7; z_7:=z_21^3; P6:=ProjectiveSpace(K,6); X:=Scheme(P6,[ -x_1*x_2+x_0*x_3, -x_1*x_3+x_0*x_4, -x_3^2+x_2*x_4, -x_1*x_4+x_0*x_5, -x_3*x_4+x_2*x_5, -x_4^2+x_3*x_5, -x_1*x_5+x_0*x_6, -x_3*x_5+x_2*x_6, -x_4*x_5+x_3*x_6, -x_5^2+x_4*x_6, x_0^3-x_6^2*x_2+x_2^2*x_3, x_0^2*x_1-x_6^2*x_3+x_2^2*x_4, x_0*x_1^2-x_6^2*x_4+x_2^2*x_5, x_1^3-x_6^2*x_5+x_2^2*x_6 ]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=Matrix([ [0,z_7^-1,0,0,0,0,0], [z_7,0,0,0,0,0,0], [0,0,0,0,0,0,-z_7^3], [0,0,0,0,0,-z_7^-2,0], [0,0,0,0,-1,0,0], [0,0,0,-z_7^2,0,0,0], [0,0,-z_7^4,0,0,0,0] ]); B:=Matrix([ [0,z_21^-5,0,0,0,0,0], [z_21^-2,0,0,0,0,0,0], [0,0,0,0,0,0,-z_21^8], [0,0,0,0,0,-z_21^11,0], [0,0,0,0,z_3+1,0,0], [0,0,0,-z_21^-4,0,0,0], [0,0,-z_21^-1,0,0,0,0] ]); Order(A); Order(B); Order( (A*B)^-1); GL7K:=GeneralLinearGroup(7,K); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); // (32,11) K:=CyclotomicField(8); i:=z_8^2; P6:=ProjectiveSpace(K,6); X:=Scheme(P6,[x_3*x_5+x_4*x_6, x_0^2+x_1*x_5+z_8^2*x_2*x_6, x_1*x_4+z_8^2*x_2*x_3+x_5*x_6, x_1*x_2+x_3*x_4, x_1*x_6+z_8^3*x_4*x_5, x_2*x_5+z_8*x_3*x_6, x_1^2-i*x_3^2-z_8^3*x_5^2, x_2^2+i*x_4^2+z_8^3*x_6^2, -i*x_2*x_4+z_8^3*x_3^2, x_1*x_3-z_8^3*x_4^2]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=Matrix([ [-1,0,0,0,0,0,0], [0,0,-1,0,0,0,0], [0,1,0,0,0,0,0], [0,0,0,0,-i,0,0], [0,0,0,-i,0,0,0], [0,0,0,0,0,0,i], [0,0,0,0,0,i,0] ]); B:=Matrix([ [i,0,0,0,0,0,0], [0,1,0,0,0,0,0], [0,0,i,0,0,0,0], [0,0,0,-1,0,0,0], [0,0,0,0,-i,0,0], [0,0,0,0,0,-1,0], [0,0,0,0,0,0,i] ]); Order(A); Order(B); Order( (A*B)^-1); GL7K:=GeneralLinearGroup(7,K); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); // (32,10) K:=CyclotomicField(16); P6:=ProjectiveSpace(K,6); X:=Scheme(P6,[ x_1*x_6+z_16^6*x_2*x_5+x_3*x_4, x_1*x_2+x_5*x_6, x_0^2+x_1*x_6-z_16^6*x_2*x_5, x_3*x_6-z_16^4*x_4*x_5, x_1^2-z_16^7*x_4^2-z_16^6*x_5^2, x_2^2+z_16^3*x_3^2-z_16^10*x_6^2, -z_16^2*x_2*x_6+(z_16^16+z_16^8)*x_4^2-z_16^7*x_5^2, x_1*x_5+(-z_16^12-z_16^4)*x_3^2-z_16^11*x_6^2, x_1*x_3+z_16^7*x_4*x_6, x_2*x_4+z_16*x_3*x_5 ]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=Matrix([ [-1,0,0,0,0,0,0], [0,0,-1,0,0,0,0], [0,1,0,0,0,0,0], [0,0,0,0,-z_16^2,0,0], [0,0,0,-z_16^6,0,0,0], [0,0,0,0,0,0,-z_16^6], [0,0,0,0,0,-z_16^2,0] ]); B:=Matrix([ [z_16^4,0,0,0,0,0,0], [0,0,-z_16^6,0,0,0,0], [0,-z_16^2,0,0,0,0,0], [0,0,0,0,-z_16^4,0,0], [0,0,0,z_16^4,0,0,0], [0,0,0,0,0,0,-z_16^4], [0,0,0,0,0,-z_16^4,0] ]); Order(A); Order(B); Order( (A*B)^-1); GL7K:=GeneralLinearGroup(7,K); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); // (48,48) signature (2,2,2,4) P6:=ProjectiveSpace(RationalField(),6); c_13:=1; X:=Scheme(P6,[ x_0^2 + x_4^2 + x_4*x_6 + x_5^2 - x_5*x_6 + x_6^2, x_1^2 - x_1*x_2 + x_2^2 - x_2*x_3 + x_3^2+x_4^2 + x_4*x_6 + x_5^2 - x_5*x_6 + x_6^2, (c_13^2+6)*(x_1^2 - 2*x_1*x_3 - x_2^2 + x_3^2)+c_13^2*(x_4^2 - 2*x_4*x_5 + 2*x_4*x_6 + x_5^2 - 2*x_5*x_6), (c_13^2+6)*(x_1*x_2 - 2*x_1*x_3 - 1/2*x_2^2 + x_2*x_3)+ c_13^2*(-2*x_4*x_5 + x_4*x_6 - x_5*x_6 + 1/2*x_6^2), c_13*(x_0*x_4 + x_0*x_5 + x_0*x_6)+((c_13^2+6)/2)*(x_1^2 - x_3^2)+(c_13^2/2)*(x_4^2 + 2*x_4*x_6 - x_5^2 + x_6^2), c_13*(x_0*x_4 + x_0*x_5)+((c_13^2+6)/2)*(x_1*x_2 - x_2*x_3)+(c_13^2/2)*(x_4*x_6 - x_5*x_6 + x_6^2), c_13*(2*x_0*x_4 + x_0*x_6)+((c_13^2+6)/2)*(x_2^2 - 2*x_2*x_3)+(c_13^2/2)*(2*x_4*x_6 + x_6^2), x_0*x_1 + x_0*x_3+c_13*(x_1*x_5 - x_3*x_4 - x_3*x_6), 2*x_0*x_1 - x_0*x_2+c_13*(x_1*x_6 + x_2*x_5 - x_2*x_6), x_0*x_2 - 2*x_0*x_3+c_13*(x_2*x_4 + x_3*x_6) ]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [ 0, 0, 1, 1, 0, 0, 0], [ 0, 0, -1, 0, 0, 0, 0], [ 0, 1, 1, 0, 0, 0, 0], [ 0, 0, 0, 0, -1, 1, 1], [ 0, 0, 0, 0, 0, 0, 1], [ 0, 0, 0, 0, 0, 1, 0] ]); B:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [ 0, 1, 1, 0, 0, 0, 0], [ 0, 0, -1, 0, 0, 0, 0], [ 0, 0, 1, 1, 0, 0, 0], [ 0, 0, 0, 0, 0, 0, -1], [ 0, 0, 0, 0, 1, -1, -1], [ 0, 0, 0, 0, -1, 0, 0] ]); C:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [ 0, 1, 0, 0, 0, 0, 0], [ 0, -1, -1, 0, 0, 0, 0], [ 0, 0, 0, -1, 0, 0, 0], [ 0, 0, 0, 0, -1, 0, 0], [ 0, 0, 0, 0, 0, 1, 0], [ 0, 0, 0, 0, 0, -1, -1] ]); Order(A); Order(B); Order(C); GL7Q:=GeneralLinearGroup(7,RationalField()); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); Automorphism(X,C); // (48,41) K:=CyclotomicField(12); i:=z_12^3; c_9:=1; P6:=ProjectiveSpace(K,6); X:=Scheme(P6,[ x_0^2+ x_3*x_6 - x_4*x_5, x_1^2 - x_2^2 + x_3*x_5 - x_4*x_6, (c_9^2-2*i)*x_1*x_2 + i*(x_3*x_6 + x_4*x_5), (c_9^2-2*i)*(x_1^2 + x_2^2) - c_9^2*(x_3*x_5 + x_4*x_6), c_9*(x_1*x_3 + x_2*x_4)-i*x_5^2 - i*x_6^2, c_9*(x_1*x_5 + x_2*x_6) +x_3^2 + x_4^2, x_1*x_4 + x_2*x_3+c_9*x_5*x_6, x_1*x_6 + x_2*x_5+i*c_9*(x_3*x_4), (c_9^2-2*i)*(x_1*x_3 - x_2*x_4) +c_9*(i*x_5^2 - i*x_6^2), (c_9^2-2*i)*(x_1*x_5 - x_2*x_6) -c_9*(x_3^2 - x_4^2) ]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, -1, 0, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0], [0, 0, 0, 0, 0, z_12^3, 0], [0, 0, 0, 0, 0, 0, -z_12^3], [0, 0, 0, -z_12^3, 0, 0, 0], [0, 0, 0, 0, z_12^3, 0, 0] ]); B:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, 0, z_12^3, 0, 0, 0, 0], [0, -z_12^3, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, z_12^2 - 1], [0, 0, 0, 0, 0, -z_12^2 + 1, 0], [0, 0, 0, 0, z_12^2, 0, 0], [0, 0, 0, -z_12^2, 0, 0, 0] ]); C:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, z_12], [0, 0, 0, 0, 0, z_12, 0], [0, 0, 0, 0, -z_12^3 + z_12, 0, 0], [0, 0, 0, -z_12^3 + z_12, 0, 0, 0] ]); GL7K:=GeneralLinearGroup(7,K); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); Automorphism(X,C); // (48,38) signature (2,2,2,4) K:=CyclotomicField(3); P6:=ProjectiveSpace(K,6); c_10:=1; X:=Scheme(P6,[ x_0^2+ x_3*x_5 + x_4*x_6, (2*c_10+1)*(x_1^2 + x_2^2) -c_10*(x_3*x_5 + x_4*x_6), (2*c_10+1)*x_1*x_2 -c_10^2*(x_3*x_6 + x_4*x_5), x_1^2 - x_2^2 + c_10*(x_3*x_5 - x_4*x_6), (2*c_10+1)*(x_1*x_3 - x_2*x_4)-c_10*(x_5^2 - x_6^2), (2*c_10+1)*(x_1*x_5 - x_2*x_6) -c_10*(x_3^2 - x_4^2), x_1*x_3 + x_2*x_4 + c_10*(x_5^2 + x_6^2), x_1*x_5 + x_2*x_6 + c_10*(x_3^2 + x_4^2), x_1*x_4 + x_2*x_3 +x_5*x_6, x_1*x_6 + x_2*x_5 + x_3*x_4 ]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0], [0, 0, -1, 0, 0, 0, 0], [0, 0, 0, 0, 0, z_3^2, 0], [0, 0, 0, 0, 0, 0, -z_3^2], [0, 0, 0, z_3, 0, 0, 0], [0, 0, 0, 0, -z_3, 0, 0] ]); B:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, -1, 0, 0, 0, 0, 0], [0, 0, -1, 0, 0, 0, 0], [0, 0, 0, 0, 0, -1, 0], [0, 0, 0, 0, 0, 0, -1], [0, 0, 0, -1, 0, 0, 0], [0, 0, 0, 0, -1, 0, 0] ]); C:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, 0, -1, 0, 0, 0, 0], [0, -1, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, -1], [0, 0, 0, 0, 0, -1, 0], [0, 0, 0, 0, -1, 0, 0], [0, 0, 0, -1, 0, 0, 0] ]); Order(A); Order(B); Order(C); GL7K:=GeneralLinearGroup(7,K); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); //(36,10) signature (2,2,2,6) K:=RationalField(); c_3:=1; c_6:=c_3+6; c_8:=-1; c_9:=-3; c_11:=1; P6:=ProjectiveSpace(K,6); X:=Scheme(P6,[ x_0^2+c_3*(x_3^2 - x_3*x_4 - x_3*x_5 + 1/2*x_3*x_6 + x_4^2 + 1/2*x_4*x_5 + 1/2*x_4*x_6 + x_5^2 + 1/2*x_5*x_6 + x_6^2), x_1^2 + x_1*x_2 + x_2^2+c_6*(x_3^2 - x_3*x_4 - x_3*x_5 + 1/2*x_3*x_6 + x_4^2 + 1/2*x_4*x_5 + 1/2*x_4*x_6 + x_5^2 + 1/2*x_5*x_6 + x_6^2), x_0*x_1 + c_8*(x_1^2 + 2*x_1*x_2) + c_9*(-2*x_3*x_4 - x_3*x_6 + x_4^2 + x_4*x_5 - x_5*x_6 - x_6^2), x_0*x_2 +c_8*(-2*x_1*x_2 - x_2^2)+c_9*(x_3^2 - x_3*x_5 + x_3*x_6 - x_4^2 - x_4*x_6 + x_5^2 + x_5*x_6), x_1*x_3 + x_1*x_4 + 2*x_1*x_6 + 2*x_2*x_3 - x_2*x_4 + x_2*x_6 + c_11*(x_3^2 - x_3*x_4 + 2*x_3*x_5 + 2*x_3*x_6 + x_4^2 - x_4*x_5 + 2*x_4*x_6 - 2*x_5^2 - x_5*x_6 + x_6^2), x_1*x_5 + 2*x_1*x_6 + 2*x_2*x_5 + x_2*x_6+ c_11*(2*x_3^2 -2*x_3*x_4 - 2*x_3*x_5 + x_3*x_6 + 2*x_4^2 + x_4*x_5 + x_4*x_6 - x_5^2- 2*x_5*x_6 - x_6^2), x_0*x_3 + x_1*x_4 - x_1*x_5 - x_2*x_3 + x_2*x_4 - x_2*x_6 + x_3^2 + 2*x_3*x_4 + 2*x_3*x_5 + 2*x_3*x_6 - 2*x_4^2 - 4*x_4*x_5 - 4*x_4*x_6 - 2*x_5^2 - 4*x_5*x_6 - 2*x_6^2, x_0*x_4 + x_1*x_3 - x_1*x_5 + x_2*x_4 + 2*x_3*x_4 - 2*x_3*x_6 - x_4^2 - 4*x_4*x_5 - 2*x_5*x_6 - 2*x_6^2, x_0*x_5 -x_1*x_5 - x_2*x_5 - x_2*x_6 + 2*x_3^2 - 2*x_3*x_5 + 2*x_3*x_6 - 2*x_4^2 - 2*x_4*x_6 - x_5^2 - 4*x_5*x_6, x_0*x_6 + x_1*x_5 + x_1*x_6 + x_2*x_6 + -4*x_3*x_4 - 2*x_3*x_6 + 2*x_4^2 + 2*x_4*x_5 + 4*x_5*x_6 + x_6^2 ]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0], [0, 0, 0, -1, -1, 0, 0], [0, 0, 0, 0, 1, 0, 0], [0, 0, 0, 0, 0, 0, 1], [0, 0, 0, 0, 0, 1, 0] ]); B:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, 1, -1, 0, 0, 0, 0], [0, 0, -1, 0, 0, 0, 0], [0, 0, 0, 0, 0, 1, 0], [0, 0, 0, 1, 1, 0, -1], [0, 0, 0, 1, 0, 0, 0], [0, 0, 0, 1, 0, 1, -1] ]); C:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, -1, 0, 0, 0, 0, 0], [0, 0, -1, 0, 0, 0, 0], [0, 0, 0, 0, 0, 1, 0], [0, 0, 0, -1, -1, -1, 1], [0, 0, 0, 1, 0, 0, 0], [0, 0, 0, 0, 0, 0, 1] ]); GL7K:=GeneralLinearGroup(7,K); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); Automorphism(X,C); // (32,43) signature (2,2,2,8) K:=CyclotomicField(4); P6:=ProjectiveSpace(K,6); c_8:=1; X:=Scheme(P6,[ x_0^2+ 2*x_3*x_4 - 2*i*x_5*x_6, x_1^2 + x_2^2-2*x_3*x_4 +2*i*x_5*x_6, x_3*x_6 - x_4*x_5, x_1^2 - x_2^2+c_8*(x_3*x_4 + i*x_5*x_6), x_0*x_1+x_3^2-x_4^2-i*x_5^2+i*x_6^2, x_0*x_2-x_5^2-x_6^2-i*x_3^2-i*x_4^2, x_0*x_3-x_1*x_4-i*x_2*x_4, x_0*x_4+x_1*x_3-i*x_2*x_3, x_0*x_5-i*x_2*x_6-x_1*x_6, x_0*x_6-i*x_2*x_5+x_1*x_5 ]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); A:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, -1, 0, 0, 0, 0, 0], [0, 0, -1, 0, 0, 0, 0], [0, 0, 0, -1, 0, 0, 0], [0, 0, 0, 0, -1, 0, 0], [0, 0, 0, 0, 0, 1, 0], [0, 0, 0, 0, 0, 0, 1] ]); B:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, 0, -1, 0, 0, 0, 0], [0, -1, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, -i], [0, 0, 0, 0, 0, -1, 0], [0, 0, 0, 0, -1, 0, 0], [0, 0, 0, i, 0, 0, 0] ]); C:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, -1, 0, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0], [0, 0, 0, 0, -i, 0, 0], [0, 0, 0, i, 0, 0, 0], [0, 0, 0, 0, 0, 0, -i], [0, 0, 0, 0, 0, i, 0] ]); D:=Matrix([ [-1, 0, 0, 0, 0, 0, 0], [0, 0, -1, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, i, 0], [0, 0, 0, 0, 0, 0, 1], [0, 0, 0, -1, 0, 0, 0], [0, 0, 0, 0, i, 0, 0] ]); GL7K:=GeneralLinearGroup(7,K); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); Automorphism(X,C); // (32,42) K:=CyclotomicField(8); i:=z_8^2; P6:=ProjectiveSpace(K,6); c_8:=1; c_10:=(1/2)*z_8^(-1)*c_8 -z_8; c_11:=(1/2)*z_8*c_8 -z_8^(-1); X:=Scheme(P6,[ x_0^2+x_1^2 + x_2^2, x_1*x_2+x_3*x_6 + i*x_4*x_5, x_3*x_4+x_5*x_6, x_1^2 - x_2^2+c_8*(x_3*x_6 - i*x_4*x_5), x_0*x_1+c_10*(x_3^2 + x_4^2)+c_11*(x_5^2 -x_6^2), x_0*x_2+c_10*(i*x_3^2 - i*x_4^2)+c_11*(i*x_5^2 + i*x_6^2), x_0*x_5+z_8^3*(i*x_1*x_4 - x_2*x_4), x_0*x_6+z_8^3*(x_1*x_3 -i*x_2*x_3), x_0*x_3-z_8^3*(i*x_1*x_6 - x_2*x_6), x_0*x_4-z_8^3*(x_1*x_5 -i*x_2*x_5) ]); Dimension(X); IsSingular(X); HilbertPolynomial(Ideal(X)); GL7K:=GeneralLinearGroup(7,K); A:=Matrix([ [-1,0,0,0,0,0,0], [0,0,-1,0,0,0,0], [0,-1,0,0,0,0,0], [0,0,0,0,z_8,0,0], [0,0,0,-z_8^3,0,0,0], [0,0,0,0,0,0,z_8^3], [0,0,0,0,0,-z_8,0] ]); B:=Matrix([ [-1,0,0,0,0,0,0], [0,1,0,0,0,0,0], [0,0,-1,0,0,0,0], [0,0,0,0,-z_8^2,0,0], [0,0,0,z_8^2,0,0,0], [0,0,0,0,0,0,-1], [0,0,0,0,0,-1,0] ]); C:=Matrix([ [-1,0,0,0,0,0,0], [0,-1,0,0,0,0,0], [0,0,-1,0,0,0,0], [0,0,0,-1,0,0,0], [0,0,0,0,1,0,0], [0,0,0,0,0,1,0], [0,0,0,0,0,0,-1] ]); Order(A); Order(B); Order(C); IdentifyGroup(sub); Automorphism(X,A); Automorphism(X,B); Automorphism(X,C);