  
  [1X18. Cat-1-groups[0X
  
      | [10X AutomorphismGroupAsCatOneGroup(G)[0X Inputs a group G and returns the Cat-1-group C corresponding th the crossed module G-> Aut(G).                                                          | 
      | [10XHomotopyGroup(C,n)[0X Inputs a cat-1-group C and an integer n. It returns the nth homotopy group of C.                                                                                        | 
      | [10XHomotopyModule(C,2)[0X Inputs a cat-1-group C and an integer n=2. It returns the second homotopy group of C as a G-module (i.e. abelian G-outer group) where G is the fundamental group of C. | 
      | [10X ModuleAsCatOneGroup(G,alpha,M)[0X Inputs a group G, an abelian group M and a homomorphism alpha: G-> Aut(M). It returns the Cat-1-group C corresponding th the zero crossed module 0: M-> G. | 
      | [10X MooreComplex(C)[0X Inputs a cat-1-group C and returns its Moore complex [M_1 -> M_0] as a list whose single entry is a homomorphism of groups.                                               | 
      | [10X NormalSubgroupAsCatOneGroup(G,N)[0X Inputs a group G with normal subgroup N. It returns the Cat-1-group C corresponding th the inclusion crossed module N-> G.                               | 
  
