The term "relation firm" is not a commonly used phrase, and it's unclear what context this question is referring to. However, based on some possible interpretations, I can provide an explanation.
1) If you are asking about a company or organization that specializes in maintaining relationships between different parties, then such a business could be referred to as a "relation firm." This type of company might offer services like relationship management, conflict resolution, or mediation between clients or customers.
2) Alternatively, if the question is referring to a mathematical concept related to functions and their properties, then a relation firm would describe a set of ordered pairs that satisfy certain conditions. In this context, it could refer to a specific type of function where each element in the domain has exactly one corresponding element in the range.