experimental::YangBaxterGraph – domain for Yang-Baxter graphs

experimental::YangBaxterGraph (top, operators SpectralParameters=parameters Values = values) represents the Yang Baxter graph with top element top, and operators operators.

→ Examples

Details:

Example 1:

As a first example, we construct the Yang-Baxter graph with top element [a,b,c], and the two elementary transpositions s1 and s2 as operators. The function makeOperator is used to build those operators:

makeOperator :=

proc(i)

    option escape;

begin

    w -> combinat::words::swap(w,i);

end:

s1 := makeOperator(1):

s2 := makeOperator(2):

YB := experimental::YangBaxterGraph([a,b,c], [s1,s2]):

math

s1 and s2 are just usual MuPAD functions. For example:

s1([a, b, c])

math

They furthermore satisfy the braid relations:

s1(s2(s1([a, b, c]))) = s2(s1(s2([a, b, c])))

math

Altogether, the vertices of the Yang-Baxter graph are simply all permutations of the list [a,b,c]:

YB::basis::list()

math

Background:

Reference: lectures notes of Alain Lascoux, http://phalanstere.univ-mlv.fr/ al/. FIXME.

Changes in MuPAD 3.1

New Function.