Correction: Directed capacity-preserving subgraphs: hardness and exact polynomial algorithms

In the original version of this article, Some errors were introduced in the editorial process.In particular P1-graph was incorrectly written as P 1-graph in the text.In "Definition 1" section, citation figure 5 should have been figure 4. Figures 4-6 captions had been interchanged.Fig. 4 caption should have been Fig. 6 and Fig. 5 caption should have been Fig. 4 and Fig. 6 caption should have been Fig. 5 and under the section "MCPS and MCPS1 on laminar series-parallel graphs", second sentence in the "Proof", which previously read "We can consider the different MEASs in isolation as their solutions are independent of each other: LSPs are P2graphs" but should have been "We can consider the different MEASs in isolation as their solutions are independent of each other: LSPs are P2-graphs".