You will be shown an excerpt from a computer science scientific research paper, followed by a question about the paper. Please answer the question. Do not include any text in your response other than the answer.

Context: Unlike the above approaches, our formulation does not rely on any task-specific, predefined similarity function between the input and output, nor do we assume that the input and output have to lie in the same low-dimensional embedding space. This makes our method a general-purpose solution for many vision and graphics tasks. We directly compare against several prior and contemporary approaches in Section 5.1.

Question: In order to determine whether two domains are similar or not, how could we define 'similarity'?
["Similarity" may be defined as a function between input and output, however, it may vary from one particular task or formulation to another. Therefore, the definition of similarity is task-specific.]