The coordinate algebra of a quantum symplectic sphere does not embed into any C*-algebra

In this note, we generalize a result of Mikkelsen–Szymański and show that, for every [Formula: see text], any bounded ∗-representation of the quantum symplectic sphere [Formula: see text] annihilates the first [Formula: see text] generators. We then classify irreducible representations of its coordinate algebra [Formula: see text].

Teaching Mathematics to English Learners

Recently, teachers in the United States are encountering an influx of multilingual immigrant students. The linguistic diversity can be challenging for teachers who need to think about how to foster language and disciplinary knowledge awareness in meaningful ways. Multimodal instruction (i.e., use of gesture, drawing, and movement) can serve to support conceptual understanding of emergent bilingual students in disciplinary areas such as mathematics or science. The purpose of this chapter is to investigate the interplay between gestures and mathematical concepts. This study takes place in a ninth grade ESOL Coordinate Algebra Classroom. Using systemic functional multimodal discourse analysis, the researchers analyze the teacher's gestures through a corpus of three video recorded lessons. The results show that the teacher's gestures endowed with meanings and mathematical concepts can enhance students' understandings. These findings can contribute to recent research on multimodal pedagogic practices among teachers with multilingual and multicultural students.

Howe–Moore type theorems for quantum groups and rigid -tensor categories

We formulate and study Howe–Moore type properties in the setting of quantum groups and in the setting of rigid $C^{\ast }$-tensor categories. We say that a rigid $C^{\ast }$-tensor category ${\mathcal{C}}$ has the Howe–Moore property if every completely positive multiplier on ${\mathcal{C}}$ has a limit at infinity. We prove that the representation categories of $q$-deformations of connected compact simple Lie groups with trivial center satisfy the Howe–Moore property. As an immediate consequence, we deduce the Howe–Moore property for Temperley–Lieb–Jones standard invariants with principal graph $A_{\infty }$. These results form a special case of a more general result on the convergence of completely bounded multipliers on the aforementioned categories. This more general result also holds for the representation categories of the free orthogonal quantum groups and for the Kazhdan–Wenzl categories. Additionally, in the specific case of the quantum groups $\text{SU}_{q}(N)$, we are able, using a result of the first-named author, to give an explicit characterization of the central states on the quantum coordinate algebra of $\text{SU}_{q}(N)$, which coincide with the completely positive multipliers on the representation category of $\text{SU}_{q}(N)$.

THE GROUP OF BI-GALOIS OBJECTS OVER THE COORDINATE ALGEBRA OF THE FROBENIUS–LUSZTIG KERNEL OF SL(2)

We construct, for q a root of unity of odd order, an embedding of the projective special linear group PSL(n) into the group of bi-Galois objects over uq(sl(n))*, the coordinate algebra of the Frobenius–Lusztig kernel of SL(n), which is shown to be an isomorphism at n=2.

Products of twists, geodesic lengths and Thurston shears

Thurston introduced shear deformations (cataclysms) on geodesic laminations–deformations including left and right displacements along geodesics. For hyperbolic surfaces with cusps, we consider shear deformations on disjoint unions of ideal geodesics. The length of a balanced weighted sum of ideal geodesics is defined and the Weil–Petersson (WP) duality of shears and the defined length is established. The Poisson bracket of a pair of balanced weight systems on a set of disjoint ideal geodesics is given in terms of an elementary$2$-form. The symplectic geometry of balanced weight systems on ideal geodesics is developed. Equality of the Fock shear coordinate algebra and the WP Poisson algebra is established. The formula for the WP Riemannian pairing of shears is also presented.

HEISENBERG DOUBLE VERSUS DEFORMED DERIVATIVES

Two approaches to the tangent space of a noncommutative space whose coordinate algebra is the enveloping algebra of a Lie algebra are known: the Heisenberg double construction and the approach via deformed derivatives, usually defined by procedures involving orderings among noncommutative coordinates or equivalently involving realizations via formal differential operators. In an earlier work, we rephrased the deformed derivative approach introducing certain smash product algebra twisting a semicompleted Weyl algebra. We show here that the Heisenberg double in the Lie algebra case, is isomorphic to that product in a nontrivial way, involving a datum ϕ parametrizing the orderings or realizations in other approaches. This way, we show that the two different formalisms, used by different communities, for introducing the noncommutative phase space for the Lie algebra type noncommutative spaces are mathematically equivalent.

THE ADHM CONSTRUCTION OF INSTANTONS ON NONCOMMUTATIVE SPACES

We present an account of the ADHM construction of instantons on Euclidean space-time ℝ4 from the point of view of noncommutative geometry. We recall the main ingredients of the classical construction in a coordinate algebra format, which we then deform using a cocycle twisting procedure to obtain a method for constructing families of instantons on noncommutative space-time, parametrized by solutions to an appropriate set of ADHM equations. We illustrate the noncommutative construction in two special cases: the Moyal–Groenewold plane [Formula: see text] and the Connes–Landi plane [Formula: see text].