Most variables are referenced simply be typing their names, e.g. ``R, myideal, f''. There are two special situations.
First, there are many matrices in the resulting resolution coming from
the res and nres commands. In order to use a specific
matrix in the resolution, you can use indexing to refer to the 
matrix. For example, if the name of the resolution computation is ``w'',
then ``w.3'', and ``w.(2+1)'' both refer to the third matrix of ``w''.
Arbitrary integer expressions are allowed as the index. If the value of
the index is out of range, then a matrix with zero rows and columns is
returned. This is useful when writing scripts.
Indexing starts at one. Some computations which have a single result standard basis (quotient, intersect, and modulo) create an auxiliary matrix. This matrix always has index ``0''. See section 7.2 for more details.
The second special situation occurs when entering a polynomial expression. There are possible name conflicts between names of matrices and the names of the ring indeterminates. This is resolved by requiring that each (1 by 1) matrix f occuring in a polynomial expression be surrounded by curly braces, e.g. ``a+{f}'' adds the ring indeterminate a to the polynomial f.
This problem occurs in several other places as well. .