Well, I entered your suggestion right away (along with the variable list), and as hoped got no error message. But it's almost 2 hours later and it's still chugging away. (Because of the special form of these equations, I think I could've solved them by hand in under 15 minutes. (The solution is just all Gaussian integer triples whose sum equals its product.) It did not seem to comprehend when earlier I had tried to Solve just one equation: u v w == u+v+w over the GaussianIntegers. Nor would it accept (a + b I)(c + d I)(e + f I) == a+c+e + (b+d+f)I over the Integers: error message said, idiotically enough, that it would absolutely refuse to try to solve an equation with an I in it over the Integers. Is there no way to get this dopey software to solve this fairly simple problem? --Dan
On Mar 26, 2015, at 11:48 AM, Cris Moore <moore@santafe.edu> wrote:
systems of equations have to be put in curly brackets:
Solve[ { a c e - a d h - b c h - b d e == a + c + e, b c e + a d e + a c h - b d h == b + d + h }, Integers]
although don't you also want to be clear about which variables you're solving for? - Cris
On Mar 26, 2015, at 12:43 PM, Dan Asimov <asimov@msri.org> wrote:
Can someone please explain why I got this error message:
----- In[40]:= Solve[a c e - a d h - b c h - b d e == a + c + e, b c e + a d e + a c h - b d h == b + d + h, Integers]
Solve::ivar: b c e + a d e + a c h - b d h == b + d + h is not a valid variable. -----
?