Declension table of ?ṛṣitva

Neuter	Singular	Dual	Plural
Nominative	ṛṣitvam	ṛṣitve	ṛṣitvāni
Vocative	ṛṣitva	ṛṣitve	ṛṣitvāni
Accusative	ṛṣitvam	ṛṣitve	ṛṣitvāni
Instrumental	ṛṣitvena	ṛṣitvābhyām	ṛṣitvaiḥ
Dative	ṛṣitvāya	ṛṣitvābhyām	ṛṣitvebhyaḥ
Ablative	ṛṣitvāt	ṛṣitvābhyām	ṛṣitvebhyaḥ
Genitive	ṛṣitvasya	ṛṣitvayoḥ	ṛṣitvānām
Locative	ṛṣitve	ṛṣitvayoḥ	ṛṣitveṣu

Compound ṛṣitva -

Adverb -ṛṣitvam -ṛṣitvāt