In [Math. Ann. 367 (2017), pp. 1517–1586] Bar-Natan and the first author show that solutions to Kashiwara–Vergne equations are in bijection with certain knot invariants: homomorphic expansions of welded foams. Welded foams a class knotted tubes <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-s...
