# fusionProduct(...,MaxWordLength=>...) -- Optional argument to specify the allowable length of words in the affine Weyl group when computing fusion products.

## Description

The Weyl group of a simple Lie algebra is finite; in contrast, the affine Weyl group of an affine Lie algebra is infinite. To keep Macaulay2 from trying to compute infinitely long words in this group, the default length of allowed words is set to max \{10, rank($\mathbf{g}$)+1\}. The user may override this with the optional argument "MaxWordLength". If the word length is too small, the program will return an error.

## Further information

• Default value: 10
• Function: fusionProduct -- computes the multiplicities of irreducibles in the decomposition of the fusion product of U and V
• Option key: MaxWordLength -- Optional argument to specify the allowable length of words in the affine Weyl group when computing fusion products.