Are these errors to be expected? Why do they happen?
restart;
solve({x<>10, -infinity<x , x<infinity, -infinity<y , y<infinity},{x,y});
Error, (in solver) invalid input: SolveTools:-Inequality:-LinearUnivariateSystem expects its 1st argument, eqns, to be of type ({list, set})({`<`, `<=`, `=`}), but received {x <> -infinity, x < 10}
But it works when replacing x<>10 by y<>10
restart;
solve({y<>10,-infinity<x , x<infinity, -infinity<y , y<infinity},{x,y});
{10 < y, x < infinity, y < infinity, -infinity < x}, {y <> -infinity, x < infinity, y < 10, -infinity < x}
What is the difference in the above two?
It also work when replacing x<>10 by x=10
solve({x=10, -infinity<x, x<infinity, -infinity<y , y<infinity},{x,y});
{x = 10, y < infinity, -infinity < y}
It also works when removing the y parts by keeping x<>10
solve({x<>10, -infinity<x , x<infinity},{x,y});
{y = y, 10 < x, x < infinity}, {y = y, x < 10, -infinity < x}
it also works when removing x<>10 and putting back the y stuff
solve({-infinity<x , x<infinity, -infinity<y , y<infinity},{x,y});
{x < infinity, y < infinity, -infinity < x, -infinity < y}
Why Maple gives an error for some cases and not the others?
Maple 2018.1