Roberts, Michael (1817–82), mathematician, was the eldest son of Captain Michael Roberts, of Kilmoney Abbey near Carrigaline, Co. Cork, and Elizabeth Roberts (née Townsend Stewart). His twin brother was William Roberts (1817–83), also a mathematician and scholar and fellow of TCD. Accounts of the place and date of his birth differ: according to his nephew Westropp Roberts he was born on 10 May 1817 at Kilmoney, Cork; according to the DNB (which Westropp Roberts cites) on 18 April in Peter Street, Cork. Educated at the Midleton School, Co. Cork, he entered TCD in 1833 at the age of fifteen, obtained a scholarship (1836), and graduated BA (1838) and MA (1848). He was a junior fellow of the college (1843–79) and became professor of mathematics in 1862, resigning his professorship when he was co-opted a senior fellow (1879), a position he retained until his death.
Roberts was an able mathematician, well known outside Ireland, and contributed to European journals many publications on the properties of geodesic lines, on the theory of invariants and covariants, and on hyperelliptic functions. By all accounts, he was a thoughtful, well-prepared lecturer, and he had learned well from James MacCullagh (qv) the importance of careful teaching. As professor of mathematics, he lectured to degree and fellowship candidates on the basis of the work he had accomplished before his appointment. His early lectures on the theory of invariants and covariants were based on several valuable papers he had published in Joseph Liouville's Journal de Mathématiques (1845, 1848). He had also published equations on hyperelliptic integrals, based on famous papers by Jacobi, which in turn followed on from unfinished work by Sir William Rowan Hamilton (qv) on dynamics. Again, these papers were published in important journals of the day, the Cambridge and Dublin Mathematical Journal (1848) and Nouvelles Annales de Mathématiques (1855), to which he and his brother William were regular contributors. He later published a book founded on his lecture notes, Tract on the addition of elliptic and hyperelliptic integrals (1871). Westropp Roberts lists twenty-four papers and memoirs by Roberts published in various journals (1845–62), and he continued to publish in the Annali di Matematica up to 1871. Many of his papers were written in French. While attending the Great Exhibition of 1851 in Hyde Park Roberts saw a small model of an ellipsoid made in Berlin, on which the lines of curvature were traced according to a method invented by him. He was subsequently given the model as a gift.
Roberts married Kate Drew Atkin of Merrion Square, Dublin, in 1851; they had three sons and four daughters. After several years of poor health, he died 4 October 1882 at 127 Lower Baggot St., Dublin.