Associativity certificates for Kontsevich's star-product $\star$ mod $\bar{o}({\hslash }^k)$: $k⩽6$ unlike $k⩾7$

Ricardo Buring, Arthemy V. Kiselev

The formula $\star$ mod $\bar{o}({\hslash }^k)$ of Kontsevich's star-product with harmonic propagators was known in full at ${\hslash }^{k⩽6}$ since 2018 for generic Poisson bracket…