These guidelines explain how to present mathematical results in a way that human readers can easily understand and verify, and that respects the reader’s time and energy budget.
A human reader is a first reader of the document. They have not read the document before starting to read it. Note the contrast to how an LLM understands a document: they first load the entire document into context, and then understand it with that context. So it is as easy for an LLM to understand a forward reference as a backward reference. This is extremely different for a human reader, who will usually stop reading if a sentence doesn’t make sense due to limited time (instead of reading the rest of the document).
Therefore, every sentence must make complete sense knowing only what has come before. As I mentioned, as an LLM it may be difficult to spot places where this is violated; if in doubt consider starting a small-model subagent (e.g. Luna or Haiku)