Abstract: The techniques described herein provide for comparison of tree structures. In some examples, a system according to this disclosure may receive at least a first item including a first tree structure and a second item including a second tree structure. The system may compare the first item and the second item. In particular, in performing the comparison, the system may detect a sub-tree structure type in the first tree structure and in the second tree structure. In some examples, the sub-tree structure type is one of one or more sub-tree structure types that have corresponding matching processes. Once determined, the system described herein may perform the corresponding matching process of the detected sub-tree structure type for the first tree structure and the second tree structure.