 Riemann was another influential figure in this context. He too had a strong influence on Dedekind, in two ways: by emphasizing (in his development of complex function theory) the importance of using simple, characteristic, and  “intrinsic” concepts, in contrast to “extrinsic”  properties tied to, say, particular symbolisms (Mehrtens 1979b, Laugwitz 1999, Tappenden 2005a, 2006, Ferreirós &amp; Reck 2020);  and by exploring new “conceptual possibilities”,  including the systematic study of Riemannian geometries (Stein 1988). A further example of such conceptual exploration, again very familiar to Dedekind, was the study of transfinite ordinal and cardinal numbers by his correspondent Cantor (Ferreirós 1999, chs. 2 and 6). And of course, later mathematicians influenced by Dirichlet, Riemann, Dedekind, and Cantor pushed their innovations further, including Ernst Zermelo, Emmy Noether, and Nicolas Bourbaki (Corry 2004, 2017, McLarty 2006, Kahle 2017).