8 July 2026
By Tom Collins
tom@TheCork.ie
A new mathematical model developed by researchers at Trinity College Dublin suggests County Cork could see a significant overhaul of its Dáil constituencies if advanced optimisation techniques were used to redraw electoral boundaries.
The research, known as COTHROM (Constituency Optimisation Through Hamiltonian Representation Of Mandates), uses computer algorithms to generate thousands of possible constituency maps before selecting those that best balance population equality, geographical compactness, continuity and respect for county boundaries.
While the model has national applications, County Cork was used as one of its principal case studies.
Under one of the researchers’ highest-scoring proposals, Cork South-West and Cork North-West would both become five-seat constituencies, while Cork South-Central would return four TDs. Cork North-Central and Cork East would each become three-seat constituencies.
According to the researchers, the proposed arrangement would reduce population variation between Cork’s five constituencies to less than 0.5 per cent, a marked improvement on the population imbalances found in the Electoral Commission’s 2023 review.
The trade-off, however, is that the model pays less attention to the traditional distinction between Cork city and county, with some suggested constituencies crossing those lines in pursuit of greater electoral equality.
Lead researcher Matthew Fenlon said the objective is not to produce one definitive constituency map but to make the choices involved in redistricting more transparent.
“There may not be one perfect map,” he said. “A map that preserves county boundaries very well may be worse on population balance. A map that is excellent on population balance may cut across counties more often. Instead of hiding those choices, we show them.”
The project draws inspiration from the work of Irish mathematician William Rowan Hamilton, applying concepts from theoretical physics to electoral geography. Maps are assigned “penalties” for features such as excessive population differences or unnecessary county boundary breaches, allowing the algorithm to identify the strongest overall solutions.
The researchers believe the system could significantly reduce the time required to prepare constituency recommendations while providing the Electoral Commission with objective comparisons between different mapping options.
The research team comprises Ruaidhrí Campion, Matthew Fenlon, Joshua Cooney Mercadal, Casey Farren-Colloty, Eliza Somerville and Michael A.J. Mitchell, all with backgrounds in mathematics, physics and computational modelling.
Although the proposals are purely academic and have no official status, the Cork case study demonstrates how data-driven modelling could influence future constituency reviews as Ireland’s population continues to change.
The full research paper, Constituency Optimisation Through Hamiltonian Representation Of Mandates (COTHROM): Algorithmic Redistricting of Irish Election Boundaries, is available at:
https://arxiv.org/abs/2606.20637