It's possible that:
* "m" represents a specific parameter within a *variation* or *application* of the AGM. The AGM is used in many areas, and a researcher or author might introduce a custom variable "m" for a specific purpose (like a scaling factor or an iteration counter within a specialized algorithm).
* "sat" is an abbreviation specific to a particular context or paper. Without more information about where you encountered these terms, it's impossible to say what "sat" stands for. It might be short for "saturated," "satisfied," or something completely different depending on the surrounding discussion.
To understand the meaning of "m" and "sat," you need to provide the source where you saw them used with the AGM. The context is crucial for interpretation.