Grades and Grade Projection

The grade command returns a set of integers which consist of the grades of an expression

> grade(1+e[1,2]);

> grade(2*e[1]+3*e[2]);

The project command projects out the specified grade from an expression, the grades can either be a integer or a set of integers.

> project(1+2*e[1]+3*e[2]+e[1,2],1);

> project(1+2*e[1]+3*e[2]+e[1,2],{0,2});