4 1 + y1 + y2 + y3 + y4; y1 + y1*y2 + y2*y3 + y3*y4 + y4; y1*y2 + y1*y2*y3 + y2*y3*y4 + y3*y4 + y4*y1; y1*y2*y3 + y1*y2*y3*y4 + y2*y3*y4 + y3*y4*y1 + y4*y1*y2; z0**5*y1*y2*y3*y4 - 1; TITLE : reduced cyclic 5-roots problem ROOT COUNTS : total degree : 4! = 24 multi-homogeneous Bezout bound : 24 generalized Bezout bound : 20 based on { y1 y2 y3 y4 } { y1 y3 }{ y2 y4 } { y1 }{ y2 }{ y3 }{ y4 } { y1 }{ y2 }{ y3 }{ y4 } mixed volume : 14 REFERENCES : See Ioannis Z. Emiris: `Sparse Elimination and Application in Kinematics' PhD Thesis, Computer Science, University of California at Berkeley, 1994, page 25. yi = zi/z0 This reduced the dimension of the problem by 1 and the mixed volume drops with 5. For the original problem, see G\"oran Bj\"orck and Ralf Fr\"oberg: `A faster way to count the solutions of inhomogeneous systems of algebraic equations, with applications to cyclic n-roots', in J. Symbolic Computation (1991) 12, pp 329--336. THE SYMMETRY GROUP : y1 y2 y3 y4 y4 y3 y2 y1 THE GENERATING SOLUTIONS : 7 4 =========================================================== solution 1 : t : 1.00000000000000E+00 0.00000000000000E+00 m : 2 the solution for t : y1 : 1.00000000000000E+00 6.36727435230003E-73 y2 : -3.81966011250105E-01 2.47616224811668E-73 y3 : -2.61803398874990E+00 -5.65979942426670E-73 y4 : 1.00000000000000E+00 -1.06121239205001E-73 == err : 4.785E-15 = rco : 7.860E-02 = res : 2.145E-72 == solution 2 : t : 1.00000000000000E+00 0.00000000000000E+00 m : 2 the solution for t : y1 : 3.09016994374947E-01 -9.51056516295154E-01 y2 : -8.09016994374947E-01 -5.87785252292473E-01 y3 : -8.09016994374948E-01 5.87785252292473E-01 y4 : 3.09016994374947E-01 9.51056516295154E-01 == err : 7.337E-16 = rco : 1.617E-01 = res : 2.483E-16 == solution 3 : t : 1.00000000000000E+00 0.00000000000000E+00 m : 2 the solution for t : y1 : 1.00000000000000E+00 3.70920615068742E-68 y2 : 1.00000000000000E+00 4.82196799589365E-67 y3 : -2.61803398874989E+00 1.48368246027497E-67 y4 : -3.81966011250105E-01 -1.03857772219248E-66 == err : 4.655E-15 = rco : 4.742E-02 = res : 4.441E-16 == solution 4 : t : 1.00000000000000E+00 0.00000000000000E+00 m : 2 the solution for t : y1 : -3.81966011250105E-01 2.84867032372794E-65 y2 : -3.81966011250105E-01 5.19288861096239E-66 y3 : -3.81966011250105E-01 0.00000000000000E+00 y4 : 1.45898033750316E-01 -3.32344871101593E-65 == err : 4.869E-16 = rco : 3.777E-02 = res : 5.551E-17 == solution 5 : t : 1.00000000000000E+00 0.00000000000000E+00 m : 2 the solution for t : y1 : 1.00000000000000E+00 7.07474928033337E-73 y2 : 1.00000000000000E+00 -4.52783953941336E-72 y3 : -3.81966011250105E-01 -3.53737464016669E-73 y4 : -2.61803398874989E+00 3.96185959698669E-72 == err : 4.655E-15 = rco : 4.136E-02 = res : 4.441E-16 == solution 6 : t : 1.00000000000000E+00 0.00000000000000E+00 m : 2 the solution for t : y1 : 6.85410196624969E+00 -2.65993991496909E-75 y2 : -2.61803398874989E+00 3.45446742203778E-76 y3 : -2.61803398874990E+00 7.94527507068689E-76 y4 : -2.61803398874990E+00 1.41633164303549E-75 == err : 5.029E-15 = rco : 1.653E-02 = res : 1.066E-14 == solution 7 : t : 1.00000000000000E+00 0.00000000000000E+00 m : 2 the solution for t : y1 : -8.09016994374947E-01 5.87785252292473E-01 y2 : 3.09016994374947E-01 -9.51056516295154E-01 y3 : 3.09016994374947E-01 9.51056516295154E-01 y4 : -8.09016994374947E-01 -5.87785252292473E-01 == err : 7.252E-16 = rco : 1.925E-01 = res : 5.551E-16 ==