John Kells Ingram was an Irish mathematician, economist and poet who started his career as a mathematician. He has been co-credited, along with John William Stubbs, with introducing the geometric concept of inversion in a circle.

Pettigo, also spelt Pettigoe, is a small village and townland on the border of County Donegal, Republic of Ireland, and County Fermanagh, Northern Ireland. It is bisected by the Termon River which is part of the border between the Republic of Ireland and Northern Ireland.