premise: How to clean vinyl flooring<br>Use a doormat to keep the floor clean. The substances you track into your house on your shoes are damaging to vinyl flooring. Dirt, tiny pits of gravel, and chemicals from asphalt are abrasive to the vinyl, and over time will cause it to get scratched and yellowed.
hypothesis: Scratched vinyl is very abrasive.
reason: The context doesn't say how abrasive the vinyl is.  It only says that the dirt, gravel, and chemicals are abrasive.