Adrian Richard David Mathias (born 12 February 1944) is a British mathematician working in set theory.
The forcing notion Mathias forcing is named for him.
Mathias became mathematically active soon after the introduction of forcing by Paul Cohen, and Kanamori[2] credits his survey of forcing that was eventually published as Surrealist landscape with figures[3] as being a "vital source" on forcing in its early days.
His paper Happy families,[4] extending his 1968 Cambridge thesis, proves important properties of the forcing now known as Mathias forcing. In the same paper he shows that no (infinite) maximal almost disjoint family can be analytic.
His more recent work on forcing includes the study of the theory PROVI of provident sets, a minimalist axiom system that still allows the forcing
construction to proceed.[6]
Mathias is also known for his writings around sociological aspects of logic. These include The ignorance of Bourbaki and Hilbert, Bourbaki and the scorning of logic, in which Mathias criticises Bourbaki's approach to logic; in A Term of Length 4,523,659,424,929 he shows that the number in the title is the number of symbols required for Bourbaki's definition of the number 1. Mathias has also considered claims that standard ZFC is stronger than necessary for "mainstream" mathematics; his paper What is Mac Lane missing? on this topic appeared alongside Saunders Mac Lane's response Is Mathias an ontologist?. Mathias also conducted a detailed study of the strength of a weakened system suggested by Mac Lane.[7]
References
^Kanamori, Akihiro (2016). "Mathias and Set Theory". Mathematical Logic Quarterly. 62:3: 278–294.