There is only one first author, because his role and position are irreplaceable. The relevant explanations are as follows:

On the signature of innovative works, such as scientific research papers, patents, research reports, etc. The name of the person who has made the greatest contribution to the work is usually signed at the front. Especially for the signature of scientific research papers, each journal has more detailed regulations; However, when the paper signature is used to evaluate professional titles, the weight of the first author is obviously heavier than that of the second and third authors, but lighter than the personal signature. Due to the complexity and diversity of scientific research, such as the case that a paper in bioinformatics has hundreds of signatures, the first author refers to the first few people, not just the first one; The situation of multiple first authors will be clearly marked. In addition, the first author is different from the correspondent and creative contribution, and the correspondent is often the most authoritative person in the field of papers.