Look at this: expand ( (abs(x)-x)*(abs(x)+x));
more zero divisors, but these are not algebraic!
RJF
Wolfgang Jenkner wrote:
>>Assume that A is an integral domain (that is, I is prime) and let K
>>be its field of fractions.
>>
>>
>
>Just to show that this is a real concern and that zero-divisors might
>be introduced even in cases where perhaps one wouldn't expect them:
>
>(C1) algebraic:true;
>(D1) TRUE
>(C2) tellrat(u^2=t-1,v^2=t+1);
> 2 2
>(D2) [v - t - 1, u - t + 1]
>(C3) x:rat(sqrt(2)*sqrt(u*v+t));
>(D3)/R/ SQRT(2) SQRT(u v + t)
>(C4) e:rat(x-u-v);
>(D4)/R/ SQRT(2) SQRT(u v + t) - v - u
>(C5) f:rat(x+u+v);
>(D5)/R/ SQRT(2) SQRT(u v + t) + v + u
>(C6) is(e=0);
>(D6) FALSE
>(C7) is(f=0);
>(D7) FALSE
>(C8) is(e*f=0);
>(D8) TRUE
>
>Wolfgang
>