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About: About this document makeUf4
Procedure from library ncalg.lib (see ncalg_lib).

makeUf4([p]); p an optional integer (field characteristic)

a ring, describing U(f_4)

You have to activate this ring with the 'setring' command. The presentation of U(f_4) is derived from the Chevalley representation of f_4, positive resp. negative roots are denoted by x(i) resp. y(i); Cartan elements are denoted by h(i).

LIB "ncalg.lib";
def ncAlgebra = makeUf4();
==> // coefficients: QQ
==> // number of vars : 52
==> //        block   1 : ordering dp
==> //                  : names    X(1) X(2) X(3) X(4) X(5) X(6) X(7) X(8) X(\
   9) X(10) X(11) X(12) X(13) X(14) X(15) X(16) X(17) X(18) X(19) X(20) X(21\
   ) X(22) X(23) X(24) Y(1) Y(2) Y(3) Y(4) Y(5) Y(6) Y(7) Y(8) Y(9) Y(10) Y(\
   11) Y(12) Y(13) Y(14) Y(15) Y(16) Y(17) Y(18) Y(19) Y(20) Y(21) Y(22) Y(2\
   3) Y(24) H(1) H(2) H(3) H(4)
==> //        block   2 : ordering C
==> // noncommutative relations: ...
setring ncAlgebra;
// ...  552  noncommutative relations
See also: makeUe6; makeUe7; makeUe8; makeUg2; makeUsl; makeUso5; makeUsp1.