
152 Polytope Projects
The refl ected Young graph is obtained by taking the levels P
0
, P
1
, …, P
n
of the Young graph and refl ecting them in the top rank level to obtain a new
P
n+1
which is a copy of P
n-1
new P
n+2
which is a copy of new P
n+2
and so on.
This graph is a sequential differential poset (Stanley 1990, Fomin 1994).
Figure 8.6 shows an example of refl ected dual graphs.
It is based on lifted binary trees and Binword.
The same principle of refl ection can be applied for rooted tree dual
graphs to describe RNA structuring processes. The refl ected graphs may
describe superposition of RNA structuring and de-structuring as a support
for self-evolvability ...