aś -- anekālśitsarvasya [[1.1.55]], is substituted for the Genitive 6th-Case ending as after the aṅga (stems) yuṣmad and asmad,
Thus तव and मम ॥ The indicatory श् of अश् shows that by 1.1.55, the whole of the affix अस् is to be replaced : otherwise it would have replaced only the first letter of the affix; and the affix not being a substitute-affix, rule 7.2.89, would not be applicable to it. The तव is substituted for युस्मद्, and मम for अस्मद् by 7.2.96; and तव + अ (अश्), and मम + अ = तव and मम् by (VI. I. 97).,