Subgraph isomorphism problem - Definition and Overview

In complexity theory, Subgraph-Isomorphism is a decision problem that is known to be NP-complete. The formal description of the decision problem is as follows.

Subgraph-Isomorphism(G₁, G₂)
Input: Two graphs G₁ and G₂.
Question: Is G₁ isomorphic to a subgraph of G₂?

Sometimes also name subgraph matching is used for the same problem. This name puts emphasis on finding such a subgraph and is not a bare decision problem.