http://www.mapleprimes.com/questions/144337-How-Do-I-See-If-A-Specific-Matrix-Product-Exists en-us 2026 Maplesoft, A Division of Waterloo Maple Inc. Maplesoft Document System Sun, 14 Jun 2026 02:38:42 GMT Sun, 14 Jun 2026 02:38:42 GMT The latest answers and comments added to the Question, How do I see if a specific matrix product exists? http://www.mapleprimes.com/images/mapleprimeswhite.jpg http://www.mapleprimes.com/questions/144337-How-Do-I-See-If-A-Specific-Matrix-Product-Exists http://www.mapleprimes.com/questions/144337-How-Do-I-See-If-A-Specific-Matrix-Product-Exists?ref=Feed:MaplePrimes:How do I see if a specific matrix product exists?:Comments#answer144339 <p>restart;<br>S := Matrix( [ [a_1, a_2, a_3, a_4], [b_1, b_2, b_3, b_4], [c_1, c_2, c_3, c_4], [d_1, d_2, d_3, d_4] ] );<br>eq1:=a_1*d_1 = b_1*c_1, a_2*d_2 = b_2*c_2, a_3*d_3 = b_3*c_3, a_4*d_4 = b_4*c_4;<br>R := Matrix( [ [s_1, t_1, r_1, l_1], [s_2, t_2, r_2, l_2], [s_3, t_3, r_3, l_3], [s_4, t_4, r_4, l_4] ] );<br>eq2:=s_1*l_1 = t_1*r_1,s_2*l_2 = t_2*r_2,s_3*l_3 = t_3*r_3,s_4*l_4 = t_4*r_4;<br>T := Matrix( [ [1, 0, 0, 1], [0, 1, 0, 0], [0, 1, 0, 0], [1, 0, 0, 1] ] );<br>S.R=~T;<br>convert(%,set);<br>res:=solve(% union {eq1,eq2});<br>nops([res]);<br>res[1]; # First of the ninety<br><br></p> <p>restart;<br>S := Matrix( [ [a_1, a_2, a_3, a_4], [b_1, b_2, b_3, b_4], [c_1, c_2, c_3, c_4], [d_1, d_2, d_3, d_4] ] );<br>eq1:=a_1*d_1 = b_1*c_1, a_2*d_2 = b_2*c_2, a_3*d_3 = b_3*c_3, a_4*d_4 = b_4*c_4;<br>R := Matrix( [ [s_1, t_1, r_1, l_1], [s_2, t_2, r_2, l_2], [s_3, t_3, r_3, l_3], [s_4, t_4, r_4, l_4] ] );<br>eq2:=s_1*l_1 = t_1*r_1,s_2*l_2 = t_2*r_2,s_3*l_3 = t_3*r_3,s_4*l_4 = t_4*r_4;<br>T := Matrix( [ [1, 0, 0, 1], [0, 1, 0, 0], [0, 1, 0, 0], [1, 0, 0, 1] ] );<br>S.R=~T;<br>convert(%,set);<br>res:=solve(% union {eq1,eq2});<br>nops([res]);<br>res[1]; # First of the ninety<br><br></p> 144339 Fri, 08 Mar 2013 08:25:38 Z Preben Alsholm Preben Alsholm http://www.mapleprimes.com/questions/144337-How-Do-I-See-If-A-Specific-Matrix-Product-Exists?ref=Feed:MaplePrimes:How do I see if a specific matrix product exists?:Comments#comment144415 <p>Thank you very very much!</p> <p>Thank you very very much!</p> 144415 Sat, 09 Mar 2013 21:15:56 Z Stavros Stavros