This paper gives an account of the contributions of Melvin Henriksen and John Isbell to the abstract theory of f-rings and formally real f-rings, with particular attention to the manner in which their work was framed by universal algebra. I describe the origins of the Pierce-Birkhoff Conjecture and present some other unsolved problems suggested by their work. © 2011 Elsevier B.V.
Publication Source (Journal or Book title)
Topology and its Applications
Madden, J. (2011). Henriksen and isbell on f-rings. Topology and its Applications, 158 (14), 1768-1773. https://doi.org/10.1016/j.topol.2011.06.011