BUG in SCA detection
> ring r;
> def E = nc_algebra(1,0);
> setring E;
> ideal Q = twostd(z);
> Q;
Q[1]=z
> NF( x2, Q);
x2
> NF( y2, Q);
y2
> qring QQ = Q; // NOT ALL SQUARES in Q!!!
> QQ;
// characteristic : 32003
// number of vars : 3
// block 1 : ordering dp
// : names x y z
// block 2 : ordering C
// noncommutative relations:
// yx=xy
// zx=xz
// zy=yz
// noncommutative type:5 /// SCA
// is skew constant:1
// ncref:1
// commref:1
// baseref:1
// alternating variables: [1, 3] // ALL SQUARES???
// quotient of sca by ideal
scaQ[1]=z
// quotient ring from ideal
_[1]=z
seems that SCA detection is wrong in checking for squares of anticommutative variables...
Change History (2)
Resolution: 
→ fixed

Status: 
new →
closed

Milestone: 
→ Releases 311 and higher

wrong handling of factors of sca lead to wrong sca detection. seems to be fixed now.
TODO: check all possible usage cases... later on...