A Schubert condition in the Grassmannian Gr(k,n) is encoded either by a partition l or by a bracket b.
A partition is a weakly decreasing list of at most k nonnegative integers less than or equal to n-k. It may be padded with zeroes to be of length k.
A bracket is a strictly increasing list of length k of positive integers between 1 and n.
This function writes a partition as a bracket. They are related as follows bk+1-i=n-i-li, for i=1,...,k.
i1 : l = {2,1};
|
i2 : k = 2; |
i3 : n = 4; |
i4 : partition2bracket(l,k,n)
o4 = {1, 3}
o4 : List
|
i5 : k = 3; |
i6 : n = 6; |
i7 : partition2bracket(l,k,n)
o7 = {2, 4, 6}
o7 : List
|