map(FlagBundle,FlagBundle) -- forgetful maps of flag varieties

Synopsis

• Function: map

• Usage:

  map(X,Y)

• Inputs:
  • X, an abstract flag bundle, with ranks ${a_1,..,a_n}$ of some bundle $E$
  • Y, an abstract flag bundle, with ranks ${b_1,..,b_k}$ of the same bundle $E$, and such that there are indices $0 = i_0 < i_1 < \ldots < i_n = k$ such that for all $l$ from $1$ to $n$ we have $b_(i_(l-1)+1) + \ldots + b_(i_l) = a_l$.
• Optional inputs:
  • Degree => ..., default value null,
  • DegreeLift => ..., default value null,
  • DegreeMap => ..., default value null,
• Outputs:
  • an abstract variety map, the forgetful map from $Y$ to $X$

Description

i1 : F1 = flagBundle({1,2,2,1,3})

o1 = F1

o1 : a flag bundle with subquotient ranks {1..2, 2, 1, 3}

i2 : F2 = flagBundle({3,3,3})

o2 = F2

o2 : a flag bundle with subquotient ranks {3:3}

i3 : f = map(F2,F1)

o3 = f

o3 : a map to F2 from F1