Labeled trees and the algebra of differential operators
Robert L. Grossman, Richard Gustavus Larson · Contemporary mathematics - American Mathematical Society · 1989
This paper is concerned with the effective symbolic computation of operators under composition. Examples include differential operators under composition and vector fields under the Lie bracket. A basic fact about such operators is that, in general, they do not commute. A basic fact about applied mathematicians is that they often rewrite expressions involving noncommuting operators in terms of other operators which do commute. If the original expression enjoys a certain symmetry, then the naive rewriting requires the computation of terms which in the end cancel. In this paper we analyze...