|One, number 1: in modern logic it is not possible to introduce the number one directly. It must be introduced indirectly, via existential quantification ("for at least one x ...") and universal quantification ("for all x ..."). In addition, identity is needed. See also definition, identity, logic, elementary logic, number theory, numbers.|
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|One (Number 1)||Berka I 56
Def "identical one" / 1/Schröder/Berka: "1 we call an area to which each area a is in the relation of classification, in which each area of the manifold is contained - (s) >" universe "?
K. Berka/L. Kreiser
Logik Texte Berlin 1983