We improve on and generalize a 1960 result of Maltsev. For field $F$, we denote by $H(F)$ the Heisenberg group with entries in $F$. Maltsev showed that there is copy $F$ defined $H(F)$, using existential formulas an arbitrary non-commuting pair $(u,v)$ as parameters. show interpreted computable $\Sigma_1$ no give two proofs. The first existence proof, relying Harrison-Trainor, Melnikov, R. Mill...