FOOTNOTES:
Project Gutenberg EPUB3 edition
Whitehead, Alfred North and Russell, Bertrand
Source notes
[65] The present section is based on the work of Frege, who first defined the ancestral relation. See his Begriffsschrift (Halle, 1879), Part III., pp. 55-87. Cf. also his Grundgesetze der Arithmetik, Vol. I. (Jena, 1893), §§ 45, 46 (pp. 59, 60). In this work the ancestral relation is used to prove the properties of finite cardinals and .