试题求解
凤凰 2004-12-21 01:56:29 1.Build the Sylvester matrix corresponding to the polynomials in the sub-resultant lecture, i.e:
A(x)= x8+x6-3x4-3x³+8x²+2x-5;
B(x)= 3x6+5x4-4x²-9x+21
Run Bareiss’s algorithm on this to compute the determinant. Note that you have to deal with the case of zero elements on the diagonal.
2.Emulate the Buchberger algorithm on cyclic-3, i.e.:
a+b+c
ab+bc+ca
abc-1
By this I mean that each s-polynomial should be computed and reduced under human control, i.e. the most sophisticated MAPLE commands you can use are of the form s:= 28x*f1-3*y*f2 or S:= s-7*z*f3. how many S-polynomials do you compute? How many of them reduce to zero?
3.Compute, via the Faugère-Gianni-Lazard-Mora(FGLM) algorithm, a purely lexicographical Gröbner base for the cyclic-5 problem: i.e:
a+b+c+d+e
ab+bc+cd+de+ea
abc+bcd+cde+dea+eab
abcd+bcde+cdea+deab+eabc
abcd-1
Hence deduce the number of solutions and a description of them.