Among them is Yahyā ibn Abī Kathīr: he narrated from a transmitter named Hishām, and a Hishām narrated from him in turn. The teacher above him is Hishām ibn ʿUrwah—one of his contemporaries—while the narrator who reports from him is Hishām ibn Abī ʿAbdillāh al-Dastuwāʾī.
Another instance is Ibn Jurayj: he transmitted from Hishām, and Hishām transmitted from him; the upper narrator is Hishām ibn ʿUrwah, and the lower is Hishām ibn Yūsuf al-Ṣanʿānī.
A further example concerns al-Ḥakam ibn ʿUtaybah: he reported (1) from Ibn Abī Laylā, and Ibn Abī Laylā reported (2) from him. The elder of the two is ʿAbd al-Raḥmān, while the younger is Muḥammad ibn ʿAbd al-Raḥmān just mentioned.
Many other examples could be cited (3).
[Identifying Single-Name Narrators]
Another important branch of this discipline is recognizing the narrators known only by a single name. Several leading scholars have compiled such lists. Some did so without any further restriction, such as Ibn Saʿd in al-Ṭabaqāt, Ibn Abī Khaythamah (4), al-Bukhārī in his two Tārīkh works (5), and Ibn Abī Ḥātim (6) in al-Jarḥ wa-l-Taʿdīl (7).