Simplicity of a Weyl algebra in characteristic zero (source code)

= Simplicity of a Weyl algebra in characteristic zero

In a nonzero <two-sided ideal> choose an element of least <Bernstein filtration> degree. Commuting it with any position or differentiation generator lowers degree, so all such commutators vanish. The <ordered monomial basis of a Weyl algebra> and <characteristic zero> then force it to be a nonzero scalar. The <ideal> is the whole <ring>. The argument fails in positive characteristic, when powers of the generators can be central.