# Packing Sets¶

Packing sets are sets $B$ of variables where

$\sum_{i \in B} x_i \leq 1$

Packing sets may include variables from multiple graphs as well as non-graph variables. Add packing sets using the addPackingSet() function like

# packing set x1 + x2 <= 1

The dynamic-programming algorithm exploits packing sets to construct $B$-elementary paths. That is, paths that only uses one edge (variable) in the packing set $B$.