1

Need help with this proof using Ferrers' graph or otherwise.

Show that the number of partitions of $r+k$ into $k$ parts is equal to

  1. The number of partitions of $r + {k+1 \choose 2}$ into $ k $ distinct parts
  2. The number of partitions of $r$ into parts of size at most $k$
MJD
  • 65,394
  • 39
  • 298
  • 580
Neel
  • 11

1 Answers1

1

(i) Take the diagram of an arbitrary partition of $r+k$ into $k$ parts, then add $0$ to the smallest part, add $1$ to the second smallest part, add $2$ to the third, $\ldots$ add $(k-1)$ to the largest part and what have you got?

(ii) Take the diagram of an arbitrary partition of of $r+k$ into $k$ parts, then subtract $1$ from each part and what have you got? Now reflect it so rows become columns and columns become rows and what have you got?

Henry
  • 157,058