ओं तत्सदिति श्रीमद्भगवद्गीतासूपनिषत्सु ब्रह्मविद्यायां योगशास्त्रे श्रीकृष्णार्जुनसंवादे अर्जुनविषादयोगो नाम प्रथमोऽध्याय: ।

oṃ tat-sad-iti śrīmad-bhagavad-
gītāsūpaniṣatsu brahma-vidyāyāṃ
yoga-śāstre śrīkṛṣṇārjuna-saṃvāde arjuna-
viṣāda-yogo nāma prathamo’dhyāya:

Om – the symbol of Brahman, tat – that singular Reality (Brahman), sat – the ever abiding presence (Brahman).

Thus ends the first chapter entitled Arjuna-viṣāda Yoga during the Srikrishna-Arjuna dialogue in Śrīmad Bhagavad Gita, constituting Yoga-śāstra, which falls within Brahmavidya as presented in the Vedic Upanishads.