And when san (Desiderative) follows, gami is the substitute of ṇ when the sense is not that of 'informing'.,
जिगमिषति 'wishes to go' जिगमिषतः, जिगमिषन्ति. But अर्थान् प्रतीषिषति 'he wishes to inform the meaning.' So also with इक्, as अधिजिगमिषति. The yogavibhaga indicates that the anuvritti of सन् only runs in the next sutra and not of णि. The form is thus evolved in the Parasmaipada; सन् + गम् = गम् + गम् + स 6.1.9 = ग + गम् + स 7.4.60 = ज + गम् + स 7.4.62 = ज + गम् + इट् + स 7.2.50 = जिगमिष, and then we add the personal terminations.,