AbstractOrientedSimplicialComplex

 Author: Kurt Pagani
 Date Created: Wed Feb 17 17:19:51 CET 2021
 License: BSD
 References:
 Description:

 sign(A,B) computes the sign of the merge of the ordered sets A,B
 of positive integers regarding the (ordered) union of A and B.
 Note: sign(A,B)=0 if intersect(A,B) is empty.

 degree(A) gives the degree of the leading monomial.

 D(X,i) computes the i-th partial derivative, i.e. more precisely
 the i-th partial boundary. For instance D(X1*X2,1)=X2, and
 D(X1*X2,2)=-X1.

 D(X)=sum(D(X,i),i=1..) computes the boundary of X.