Brahma Sūtra 1.4.6
Śaṅkara
Advaita Vedānta
Sūtra
त्रयाणामेव चैवमुपन्यासः प्रश्नश्च
trayāṇāmeva caivamupanyāsaḥ praśnaśca
Sūtra translation
And there is question and explanation relative to three things only (not to the pradhâna).
To the same conclusion we are led by the consideration of the circumstance that the Kathavallî-upanishad brings forward, as subjects of discussion, only three
Rāmānuja
Viśiṣṭādvaita Vedānta
Sūtra
त्रयाणामेव चैवमुपन्यासः प्रश्नश्च
trayāṇāmeva caivamupanyāsaḥ praśnaśca
Sūtra translation
And of three only there is this mention and question.
In the Upanishad under discussion there is mention made of three things only as objects of knowledge—the three standing to one another in the
Madhva
Dvaita Vedānta
Numbered 1.4.7 in this text
Sūtra
त्रयाणामेवचैवमुपन्यासः प्रश्नश्च
trayāṇāmevacaivamupanyāsaḥ praśnaśca
Sūtra translation
And (because of the whole Upanishad dealing) with the explanation of, as well as the question on, the same three topics.
For the Kâthaka Upanishad treats only of the three boons prayed for by Nachiketas, viz., reconciliation to his father, the sacred fire leading to