First, it is shown from a new viewpoint that the universal enveloping algebra generates a Lie subgroup of a known classical infinite dimensional Lie group, therefore the enlargability is ensured.

• 首先,本文从一个新的视角证明泛包络代数作为无穷维李代数生成一个标准无穷维李群的子李群,从而保证了泛包络代数的可扩张性;