# Comment on: Multipartite entanglement in four-qubit graph state

## TL;DR

This paper comments on previous work calculating entanglement in four-qubit graph states, highlighting limitations of the Scott measure and clarifying the relationship between different entanglement measures.

## Contribution

It reveals limitations of the Scott measure in four-qubit systems and confirms that Q_2 is not always greater than Q_3, clarifying entanglement measure relationships.

## Key findings

- Scott measure limits prevent Q_3 calculation in four-qubit systems
- Q_2 is not necessarily greater than Q_3 in four-qubit graph states
- Counterexample confirms previous conclusions about entanglement measures

## Abstract

The following comment is based on an article by M. Jafarpour and L. Assadi [Eur. Phys. J. D 70, 62 (2016), doi:10.1140/epjd/e2016-60555-5] which with an exploitation of Scott measure (or generalized Meyer-Wallach measure) the entanglement quantity of four-qubit graph states has been calculated. We are to reveal that the Scott measure (Q_m) nominates limits for m which would prevent us from calculating Q_3 in four-qubit system. Incidentally in a counterexample we will confirm as it was recently concluded in the mentioned article, the Q_2 quantity is not necessarily always greater than Q_3.