Question: algsubs & Operators

Dear All

I am trying to substitute an expression that contains hermitian operators where the ordering is crucial.  I have tried algsubs and simplify-sidderels, but they both do nothing.

I am trying to substitute;

a + b*c*b = R

where all are defined as hermitian operators in the Physics package.

into an expression;

H = - a - b*c*b

but nothing happens...

However, when I substitute a = R - b*c*b, rather than getting H = -R, I get;

H = -R + c*b - b*c*b

hence the ordering on the remainder terms which should cancel, but donot.

On another term I get the error message "Error, (in algsubs) no variables appearing rationally in pattern" when there are considerably more hermitian operators and terms.  I don't know if this message is related to the previous comment however.

Cheers;

Robert Ward