Generators for Coulomb branches of quiver gauge theories

We study the Coulomb branches of $3d$ $\mathcal{N}=4$ quiver gauge theories, focusing on the generators for their quantized coordinate rings. We show that there is a surjective map from a shifted Yangian onto the quantized Coulomb branch, once the deformation parameter is set to $\hbar =1$. In finite ADE type, this extends to a surjection over $\mathbb{C}[\hbar]$. We also show that these algebras are generated by the dressed minuscule monopole operators, for an arbitrary quiver (this is similar to the proof of Theorem 4.29 in arXiv:1811.12137). Finally, we describe how the KLR Yangian algebra from arXiv:1806.07519 is related to Webster's extended BFN category. This paper provides proofs for two results which were announced in arXiv:1806.07519.