ABSTRACT
Tensors are great tools for doing practical calculations in SU(3) and in many other groups as well. The idea of tensors is closely related to the idea of a wave function in quantum mechanics. A tensor is just a “wave-function”, because we can find v by taking the matrix element of v with the tensor product state. We can use tensors to decompose tensor products explicitly. The general strategy for doing the decompositions is to make irreducible representations out of the product of tensors, and then express the original product as a sum of terms proportional to various irreducible combinations. A very simple application of tensor methods is the calculation of the dimension of the irreducible representation.
