Spahn applications of operads

References

• 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 $\mathbb{Q}$.

• Ralph M.Kaufman, On Spineless Cacti, Deligne’s Conjecture and Connes–Kreimer’s Hopf Algebra, arXiv:math/0308005v4 [math.QA]