In a biological setting, we usually are interested on identifying tree structures (clusters) that are not necesarily identical. Here we define a series of different levels of similarity we want to recognise between the structures being compared.
Keep in mind that at all times, we are considering the comparison of nodes within a tree-like structure (a Dendrogram).

ISOMORPHIC two trees are isomorphic if one can be obtained from the other simply by performing a series of flips on its branches. The sub-graph components of each tree, as well as their overall structure (links) is retained on both structures

BIOISOMORPHIC

REARRANGED

CONTAINED we define a tree to be contained by a second tree if the