dṛḍhamūlapratiṣṭhite 'ti / dṛḍhā anavasthādidoṣair akampyā mūlapratiṣṭhā yasya sa tathā, tadbhāvastattvam //
"[That which] has its root firmly established" means that whose root-establishment is firm [and] unshakeable due to being free from defects such as infinite regress; such is its nature.