Dear all, please consider the attached patches: GiNaC is able to check whether expressions are sums of possymbols. We can use that to evaluate some step functions immediately: 0001-Evaluate-step-whenever-possible.patch This should be a generic transformation from an integral with a step function to step functions times integrals without: 0002-Integrate-when-integrand-is-a-product-with-a-step-fu.patch This patch implements Pauli matrices in the same manner as in color.cpp (shamelessly borrowed...): 0003-Implementation-of-Pauli-matrices.patch As opposed to the color algebra, a product of pauli objects can always be reduced to a linear combination of single pauli objects: 0004-New-function-pauli_normalize.patch Best wishes, Matthias Dellweg