Deformations of T-log-symplectic log-canonical Poisson structures and symmetric Poisson CGL extensions

Abstract: For a complex algebraic torus $\mathbb{T}$, we study $\mathbb{T}$-invariant Poisson deformations of $\mathbb{T}$-log-symplectic log-canonical Poisson structures on $\mathbb{C}^n$. We show that, under mild assumptions, every $\mathbb{T}$-invariant first-order deformation with no $(\mathbb{C}^\times)^n$-invariant component is unobstructed. As an application, we prove that a special class of $\mathbb{T}$-log-symplectic log-canonical Poisson structures on $\mathbb{C}^n$, namely those defined by the so-called $\mathbb{T}$-action data, can be canonically deformed to $\mathbb{T}$-invariant algebraic Poisson structures on $\mathbb{C}^n$ that are (strongly) symmetric Poisson CGL extensions (of $\mathbb{C})$ in the sense of Goodearl-Yakimov. In particular, we construct (strongly) symmetric CGL extensions from any sequence of simple roots associated to any symmetrizable generalized Cartan matrix $A$. When $A$ is of finite type, our construction recovers the standard Poisson structures on Bott-Samelson cells and on generalized Schubert cells, which are closely related to the (standard) cluster algebra structures on such cells.