Definitions of a group and a field by independent postulates
Definitions of a group and a field by independent postulates
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通过独立假设定义群和域
DOI:
10.1090/s0002-9947-1905-1500706-2
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发表时间:
1905
影响因子:
1.3
通讯作者:
L. Dickson
中科院分区:
文献类型:
--
作者:
L. Dickson
1. The simple definition here given for a general abstract group relates as to origin and character to Professor Moore's two definitions, Transactions, vol. 3 (1902), pp. 485-492. A few days before the appearance of the addition, Transactions, vol. 5 (1904),p. 549, to his paper, Professor Moore remarked to me that one of his postulates relating to an inverse was redundant, meaning postulate ( 3" ) of his second definition. I thought the reference was to his first definition and attempted to reconstruct the proof of a redundancy, there absent. This attempt led me to alter his postulate (4;) to read aa'r = ir instead of a',a = ir and to note that postulate (3;) becomes redundant in the altered set, thus obtaining the present definition. Subsequently I learned that Professor Moore, in his proof of the redundancy of (3") in his second definition, had obtained relations J sufficient to establish the present definition but had not applied them to set up the definition itself. The present postulates for a general group possess the desirable property that they remain independent within sets of postulates for special classes of groups, the specialization being either in the direction of the number ( n > 1 ) of elements or their commutativity (§§ 3-5). The definition of a field (§ 6), based on the present definition of a group, has evident advantages over the earlier definitions. § The postulates for a field remain independent under an assumption that the set is finite, or forms an enumerable infinitude, or a non-enumerable infinitude.