वामदेवाड्ड्यड्ड्यौ

The affixes ड्यत् and ड्य come in the sense of the साम वेद seen after the word वामदेव , being in the Instrumental -3rd case in construction.
Karika
सिद्धे यस्येतिलोपेन किमर्थं ययतौ डितौ ।
ग्रहणं माऽतदर्थे भूद्वामदेव्यस्य नञ्स्वरे ॥

This debars अण् ॥ Thus वामदेवेन दृष्टं साम = वामदेव्यं॑ or वामदेव्यं꣡ ॥ The indicatory त् in 'dyat' shows that य has svarita accent 6.1.125.

Q. What is the use of the indicatory ड्?

Ans. The final syllable is elided when a डित् affix is added, by 6.4.143.

Q. The final अ of वामदेव would have been elided without making this affix डित्, by the rule 6.4.148, then what is the use of making this affix डित्?

Ans. Well, the author here indicates by jnapaka, the existence of these two maxims of interpretation, viz. Paribhashas निरनुबन्धकग्रहणे न सानुबन्धकस्य "when a term void of anubandhas is employed, it does not denote that which has an anubandha attached to it". तदनुबन्धकग्रहणे नातदनुबन्धकस्य "when a term with one or more anubandhas is employed it does not denote that which, in addition to those, has another anubandha attached to it".

For had य and यत् been only taught instead of 'dya' and 'dyat', then by rule 6.2.156 the final of such word, with the negative particle अ, would take udatta on the final, but that is not the case. Therefore अवामदेव्यं is not finally acute, but has acute on the first syllable, taking the accent of the Indeclinable 6.2.2. As अ꣡वामदेव्यं ॥