Given finite sets $A,B,C$ of finite strings, does there exist some $x,y \in A$ and some $z$ such that $x.z \in B$ and $y.z \in C$ hold (where $x.z$ denotes the concatenation of $x$ and $z$)? That is, do $B$ and $C$ contain a pair of sequences with a common suffix such that the respective remaining prefixes are both contained in $A$?

For example, $A := \{a,b,cd\}$, $B := \{ae,ada\}$, $C := \{bd,cdda\}$ satisfy the above condition for $a, cd \in A$, $ada \in B$, and $cdda \in C$.

Does this problem have an established name?

  • $\begingroup$ Even the problem with a single prefix in $A$ does not seem to have a name. You might call it a "prefix.suffix search", though the dot as a concatenation operator is not universal. Or "concatenation search". Or conversely, a "split string search" or "split string match" ? $\endgroup$ Mar 9, 2022 at 10:21
  • $\begingroup$ Your variant would be a "2,1-concatenation search". $\endgroup$ Mar 9, 2022 at 10:24
  • $\begingroup$ You can address this problem by performing a suffix search for all elements of $B$ in $C$. Then for every matching subsets, check for at least two elements in the intersection with $A$. $\endgroup$ Mar 9, 2022 at 10:30


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