Domino Treewidth by Bodlaender, Engelfriet

https://www.doi.org/10.1006/jagm.1996.0854

@article{dominoTreewidth1997,
author = {Hans L. Bodlaender and Joost Engelfriet},
doi = {10.1006/jagm.1996.0854},
issn = {0196-6774},
journaltitle = {Journal of Algorithms},
number = {1},
pages = {94-123},
title = {Domino Treewidth},
volume = {24},
year = {1997},
}

page 3 : domino treewidth – A tree-decomposition … is a domino tree-decomposition, if … every vertex belongs to at most two sets $X_i$. The domino treewidth of a graph $G$ is the minimum width over all domino tree-decompositions of $G$.