Maple produces an error when adding positive constraints - maple

Question

I am testing Maple 2021 on a simple system of equations in x,y,z,t:
solve({x = 1, a*z^2 = c*t*x, c*x^2 = a*y*z, d*y^2 = b*t*x, 0 < a, 0 < b, 0 < c, 0 < d}, {t, x, y, z});
The results look correct (sorry for the formatting, this is copy-pasted directly from Maple):
/[[ / (1/2) (1/2) (1/4) (1/4)
|[[ | d c c b
PIECEWISE|[[< t = -------------, x = 1, y = -------------,
|[[ | (1/2) (1/2) (1/4) (1/4)
\[[ \ a b d a
(3/4) (1/4)\ / (1/2) (1/2)
c d | | d c
z = ------------- >, < t = -------------, x = 1,
(3/4) (1/4)| | (1/2) (1/2)
a b / \ a b
(1/4) (1/4) (3/4) (1/4)\ ]
c b c d | ]
y = - -------------, z = - ------------- >],
(1/4) (1/4) (3/4) (1/4)| ]
d a a b / ]
] \
] |
And(0 < a, 0 < b, 0 < c, 0 < d)], [[], otherwise]|
] |
] /
I only want to obtain positive solution, so I add such constraint:
solve({c*x^(2)=a*y*z,d*y^(2)=b*t*x,a*z^(2)=c*t*x,x=1,a>0,b>0,c>0,d>0,x>0,y>0,z>0,t>0},{x,y,z,t});
However, I obtained an error:
Error, Got internal error in Typesetting:-Parse :
"'_Inert_DELAYLESSTHAN' is not a valid inert form"
Thanks for your help!

Answer 1

I do not get such an error (in displaying the result), using Maple 2021.1.
I use lprint below only so that I can paste the result in here more easily.
restart;
kernelopts(version);
Maple 2021.1, X86 64 LINUX, May 19 2021, Build ID 1539851
sol:=solve({c*x^(2)=a*y*z,d*y^(2)=b*t*x,
a*z^(2)=c*t*x, x=1,
a>0,b>0,c>0,d>0,x>0,y>0,z>0,t>0},
{x,y,z,t}):
lprint(%);
piecewise(And(0 < a,0 < b,0 < c,0 < d,0 <
d*c^2*b/(c^3*d*a*b^3)^(1/2),0 < 1/a/b
*(c^3*d*a*b^3)^(1/4),0 <
c*b/(c^3*d*a*b^3)^(1/4),0 <=
c*b/(c^3*d*a*b^3)^(1/4)),
[{t = d^(1/2)*c^(1/2)/a^(1/2)/b^(1/2), x = 1,
y = c^(1/4)*b^(1/4)/d^(1/4)/a^(1/
4), z = 1/a^(3/4)/b^(1/4)*c^(3/4)*d^(1/4)}],
And(0 < a,0 < b,0 < c,0 < d,0 < d*c
^2*b/(c^3*d*a*b^3)^(1/2),0 < 1/a/b*
(c^3*d*a*b^3)^(1/4),0 < c*b/(c^3*d*a*b^3)^(1
/4),1/a/b*(c^3*d*a*b^3)^(1/4) <
0,c*b/(c^3*d*a*b^3)^(1/4) < 0),[{t =
d*c^2*b/(c^3*d*a*b^3)^(1/2), x = 1, y =
c*b/(c^3*d*a*b^3)^(1/4), z = 1/a/b*(c^3*d*a*b^3)^
(1/4)}, {t = d*c^2*b/(c^3*d*a*b^3)^(1/2), x = 1,
y = -c*b/(c^3*d*a*b^3)^(1/4),
z = -1/a/b*(c^3*d*a*b^3)^(1/4)}],
And(0 < a,0 < b,0 < c,0 < d,0 < d*c^2*b/(c^3*d
*a*b^3)^(1/2),1/a/b*(c^3*d*a*b^3)^(1/4) <
0,c*b/(c^3*d*a*b^3)^(1/4) < 0,c*b/(c^
3*d*a*b^3)^(1/4) <= 0),[{t =
d^(1/2)*c^(1/2)/a^(1/2)/b^(1/2), x = 1, y = -c^(1/
4)*b^(1/4)/d^(1/4)/a^(1/4), z =
-1/a^(3/4)/b^(1/4)*c^(3/4)*d^(1/4)}],[])
combine(sol) assuming
a>0,b>0,c>0,d>0,x>0,y>0,z>0,t>0:
lprint(%);
[{t = (d*c/b/a)^(1/2), x = 1, y = 1/d/a*
(c*b*d^3*a^3)^(1/4), z = 1/a/b*(c^3*d*a
*b^3)^(1/4)}]