# [Intro QM] A bit confused on spin of system notation

1. In Griffiths, in the section where he discusses the 'total' spin of two spin 1/2 particles (''Addition of angular momenta'') he starts of using a notation new to me. Namely ##\chi=\chi_1\chi_2## where I know what ##\chi_1## and ##\chi_2## represent independently, which has been discussed in the previous chapter. They were a representation of the spin relative to a basis before, and hence vectors. How to read this notation, is it a product? Is it some union-type of thing?

DEvens