dim:=6$
REFALGTEX:={M5}$
 NONCOM x;
  FOR i:=1:DIM DO
  FOR j:=i:DIM DO
         x(i)*x(j):=
    IF i=1 THEN
       IF j=3 THEN x(5) ELSE
       IF j=4 THEN x(6) ELSE 0
    ELSE
    IF i=2 THEN
       IF j=3 THEN - x(6) ELSE
       IF j=4 THEN x(5) ELSE 0
    ELSE 0;

 FOR i:=1:DIM-1 DO
 FOR j:=i+1:DIM DO
       x(j)*x(i):=-x(i)*x(j);
%Les projecteurs de la base duale
NONCOM X,V ;
FOR i:=1:DIM DO
    FOR j:=1:DIM DO
       V(i)*X(j):= IF i=j THEN 1 ELSE 0;
END$