Celebratio Mathematica

S. Mac Lane: “Dia­grams, equa­tions and the­or­ies in cat­egor­ies,” pp. 143–​149 in Uni­ver­sal al­gebra and its links with lo­gic, al­gebra, com­bin­at­or­ics and com­puter sci­ence (Darm­stadt, Ger­many, 4–6 Feb­ru­ary 1983). Edi­ted by P. Bur­meister, B. Ganter, C. Her­rmann, K. Keimel, E. Po­gun­tke, and R. Wille. Re­search and Ex­pos­i­tion in Math­em­at­ics 4. Hel­d­er­mann (Ber­lin), 1984. MR 792509 Zbl 0547.​18002 incollection