The affix śyan comes after a root of the divādi class when a sārvadhātuka affix denoting the agent follows.,
This debars शप्. The servile न of श्यन् is for the sake of accent (VI. I. 197), showing that the udatta accent falls on the radical verb and not on the affix; and the indicatory श makes the affix sarvadhatuka; as दिव् + श्यन् + तिप् = दीव् + य + ति 7.2.77 = दीव्यति; so also सीव्यति. The Divadi verbs belong to the Fourth conjugation.,