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GradedLieAlgebras :: extRepRing

extRepRing -- the ring representation of the Ext-algebra

Synopsis

Description

If minmodelLie (or extBasisLie or extTableLie) of a Lie algebra L is computed up to a certain degree, then the representation of ExtUL(k,k), where k is L.field, as linear polynomials may be obtained as L.cache.extRepRing.

i1 : L=lieAlgebra{a,b}/{a b}

o1 = L

o1 : LieAlgebra
i2 : extBasisLie 3

o2 = {ext , ext , ext }
         0     1     2

o2 : List
i3 : E=L.cache.extRepRing

o3 = E

o3 : PolynomialRing
i4 : (ext_0+2*ext_1) ext_1

o4 = -ext
         2

o4 : E

See also

For the programmer

The object extRepRing is a symbol.