zhè / gè / gōng / shì / lǐ / de / ài / pǔ / xī / lóng / dài / biǎo / yí / gè / hěn / xiǎo / de / zhèng / shù这个公式里的艾普西隆代表一个很小的正数。In this formula, epsilon represents a very small positive number.