context: Galois theyory of renormalizations, renormalization, combinatorics, cyclotomic closure of $\mathbb{Q}$ ## References * Michael Polyak, Feynman diagrams for pedestrians and mathematicians, 2004, [arXiv:math/0406251v1 [math.GT]](http://arxiv.org/abs/math.GT/0406251) * finite dimensional Feynman diagrams, [web](http://www.ams.org/samplings/feature-column/fcarc-feynman4) * Jack Morava, the motivic Thom isomorphism, 2003. In ''appendix: motivic models for the little disk operad'' is articulated the question ''is the little disk operad defined over $\mathbb{Q}$?'' meaning: defined in the category of algebraic varieties over $\mathbb{Q}$. see also [[applications of operads]]