vähendub

Could you clarify what “vähendub” refers to? Is it a real term in a specific field (such as linguistics, mathematics, electronics, economics, etc.) or a fictional/neologistic concept you want documented? Also, should the article be in English or Finnish? If you’d like, I can provide a neutral, concise wiki-style stub for a fictional concept or proceed with a real-world topic once you specify the domain.