Quantum enveloping algebra

In mathematics, a quantum or quantized enveloping algebra is a q-analog of a universal enveloping algebra. Given a Lie algebra $\mathfrak{𝔤}$, the quantum enveloping algebra is typically denoted as $U_q(\mathfrak{𝔤})$. Among the applications, studying the $q\to 0$ limit led to the discovery of crystal bases.

The case of ${\mathfrak{𝔰}\mathfrak{𝔩}}_2$

Michio Jimbo considered the algebras with three generators related by the three commutators

$[h,e]=2e,[h,f]=-2f,[e,f]=\sinh (\eta h)/\sinh \eta .$

When $\eta \to 0$, these reduce to the commutators that define the special linear Lie algebra ${\mathfrak{𝔰}\mathfrak{𝔩}}_2$. In contrast, for nonzero $\eta$, the algebra defined by these relations is not a Lie algebra but instead an associative algebra that can be regarded as a deformation of the universal enveloping algebra of ${\mathfrak{𝔰}\mathfrak{𝔩}}_2$.

References

• Drinfel'd, V. G. (1987), "Quantum Groups", Proceedings of the International Congress of Mathematicians 986 (American Mathematical Society) 1: 798–820 

External links

• Quantized enveloping algebra at the nLab
• Quantized enveloping algebras at $q=1$ at MathOverflow
• Does there exist any "quantum Lie algebra" embeded into the quantum enveloping algebra $U_q(g)$? at MathOverflow