/// @@prerequisite opérations élémentaires 
A=[1,2,3 +5] /// \sleftarrow{\normalfont here \verb-A=[1,2,3,+5]- with a unary \verb-+-}
A=[1,2,3 *5] /// \sleftarrow{\normalfont here \verb+A=[1,2,3*5]+ with a binary \verb-*- }
A=[A,0; 1,2,3,4]