I wrote a function and would like to return reduced expressions of the form in Sage.
def LongestPermInDoubleCoset(S1,w,S2): # longest element in S1 w S2, S1,S2 are subgroups of S_n
winner = W.identity()
for u1 in S1:
for u2 in S2:
t1=u1*w*u2
if t1.length()>winner.length():
winner=t1
r=winner
return r
W=SymmetricGroup(6)
[s1,s2,s3,s4,s5] = W.simple_reflections()
S1=[W.identity(), s1]
S2=[W.identity(),s2]
t1=LongestPermInDoubleCoset(S1,s1,S2)
t2=t1.reduced_word()
t2
I obtained t2=[1,2]. But I would like to return s1*s2. How to do that? Thank you very much.