Because in the published papers and works, it is necessary to explain the words "tied for the first author", "equal contribution" and "equal contribution" of the first author, and then explain in detail the chapters and parts he is responsible for.
First of all, whether the published sci papers can be recognized as the first author depends on the specific standards of the unit and the school, and most of them are recognized, but it is better to confirm the relevant requirements with the competent department of the unit.
In general, the first author who is tied with the first author, the first author who is tied with the first author or the author who contributes with the first author will be scored according to the actual ranking, and the papers with the above marks included in sci will be regarded as the first author's score.
In other words, if the first author is tied, it must be clearly marked. In addition to paying attention to whether the unit recognizes it, it depends on how the magazine identifies the first author. Some magazines are the first author by default.
Therefore, whether the first author is recognized or not, and how to label it specifically depends on the specific situation. Different authors, different units and different journals may make different judgments.