Azarbaijan Shahid Madani UniversityCommunications in Combinatorics and Optimization2538-21285220201201Bounds on signed total double Roman domination1912061406110.22049/cco.2020.26761.1140ENL.ShahbaziAzarbaijan Shahid Madani UniversityH.Abdollahzadeh AhangarBabol Noshirvani University of Technology0000-0002-0038-8047R.KhoeilarAzarbaijan Shahid Madani University0000-0002-2981-3625Seyed MahmoudSheikholeslamiAzarbaijan Shahid Madani University0000-0003-2298-4744Journal Article20200207A signed total double Roman dominating function (STDRDF) on {an} isolated-free graph $G=(V,E)$ is a function $f:V(G)\rightarrow\{-1,1,2,3\}$ such that (i) every vertex $v$ with $f(v)=-1$ has at least two neighbors assigned 2 under $f$ or one neighbor $w$ with $f(w)=3$, (ii) every vertex $v$ with $f(v)=1$ has at least one neighbor $w$ with $f(w)\geq2$ and (iii) $\sum_{u\in N(v)}f(u)\ge1$ holds for any vertex $v$. The weight of {an} STDRDF is the value $f(V(G))=\sum_{u\in V(G)}f(u).$ The signed total double Roman domination number $\gamma^t_{sdR}(G)$ is the minimum weight of an STDRDF on $G$. In this paper, we continue the study of the signed total double Roman domination in graphs and present some sharp bounds for this parameter.http://comb-opt.azaruniv.ac.ir/article_14061_e11b84bc918c5f13db5dfa4080bc9852.pdf