@techreport{TR-IC-25-03, number = {IC-25-03}, author = {A. A. {Pereira} and C. N. {Campos}}, title = {{Extending unlocked matchings in graphs}}, month = {October}, year = {2025}, institution = {Institute of Computing, University of Campinas}, note = {In English, 09 pages. \par\selectlanguage{english}\textbf{Abstract} Let $M$ be a matching of a graph $G$ and let $S(M)$ and $U(M)$ be the sets of $M$-saturated and $M$-unsaturated vertices of $G$, respectively. A vertex $v \in U(M)$ is unlocked if there exists a vertex $u \in N(v) \cap U(M)$. The matching $M$ is unlocked if every vertex in $U(M)$ is unlocked. We say that a graph $G$ is $k$-fully-extendable if every unlocked matching $M$ in $G$ of size $k$ can be extended to a perfect matching of $G$. In this work, we study $k$-fully-extendable graphs of order $2n$, characterizing the cases $k = n-1$ and $k = n-2$. For the case $k = n-2$, we provide additional necessary conditions, based on degree bounds, as well as sufficient conditions, based on classes of graphs. } }