@article{Barišić2022, 
author = {Ana Klobučar Barišić and Antoaneta Klobučar},
title = {Double total domination number in certain chemical graphs},
year = {2022},
journal = {AIMS Mathematics},
volume = {7},
number = {11},
pages = {19629-19640},
keywords = {total domination, double total domination, hexagonal systems, molecular graph, pyrene network, hexabenzocoronene},
url = {https://www.sciopen.com/article/10.3934/math.20221076},
doi = {10.3934/math.20221076},
abstract = {Let    G be a graph with the vertex set    V  (  G  ). A set    D  ⊆  V  (  G  ) is a total k-dominating set if every vertex    v  ∈  V  (  G  ) has at least    k neighbours in    D. The total k-domination number        γ          k      t        (  G  ) is the cardinality of the smallest total k-dominating set. For    k  =  2 the total 2-dominating set is called double total dominating set. In this paper we determine the upper and lower bounds and some exact values for double total domination number on pyrene network    P  Y  (  n  ),    n  ≥  1 and hexabenzocoronene    X  C  (  n  )    n  ≥  2, where pyrene network and hexabenzocoronene are composed of congruent hexagons.}
}