I present this paper for publication to an American journal and in English for the following reason :The theory of linear algebras has been greatly extended through the work of American mathematicians.Of late, German mathematicians have become active in this theory.In particular, they have succeeded in obtaining some apparently remarkable results by using the theory of algebraic numbers, ideals, and abstract algebra, highly developed in Germany in recent decades.These results do not seem to be as well known in America as they should be on account of their importance.This fact is due, perhaps, to the language difference or to the unavailability of the widely scattered sources.This paper develops a new application of the above mentioned theories to the theory of linear algebras.Of particular importance is the fact that purely algebraic results are obtained from deep-lying arithmetical theorems.In the middle part, an account is given of the fundamental algebraic basis for these arithmetical methods.This account is more extended than is necessary for this paper, and should obviate an extended study of several German papers.I am very grateful to Professor F. T. Engstrom (New Haven) for going through the manuscript and proof with me and anglicising my many literal translations from the German.I. Statement of theorems to be proved!1. Cyclic algebras.In I, the reference field is assumed to be an algebraic number field of finite degree.}A cyclic algebra of degree over Q, is defined as an algebra A of the following type: * Presented to the Society, September 9, 1931; received by the editors May 29, 1931.f This section has also appeared recently in German in the Nachrichten von der Gesellschaft der Wissenschaften zu Gttingen, 1931. In the following, such notations as are only made complete by naming a definite reference field, may be implicitly understood to be with respect to unless another reference field is explicitly named. || See also Dickson (1 App. II).* It is unnecessary to distinguish between isomorphism (equivalence) and identity unless subalgebras of the same algebra are considered.t In the following, the general norm residue theory, recently developed by the author, is of the greatest importance.See therefore the papers Hasse (11,12, 13 II). This alternative form has been introduced by the editors to simplify typography. Hasse (1-4).I' a,Z\ Ia,Z\ I ,Z\(3-2) hr)-(-r)(ir> By (3.1) and (3.2), the symbol ((a, Z)/p) is indeed fixed except an arbitrary exponent prime to n and independent of a which may be attached.fIt is a pity that one is not able to-day to fix that exponent in a quite natural manner, i.e., without having to consider also the congruence behavior of a for prime spots different from p and with it, in principle, the law of reciprocity.Therefore, in order to obtain the complete definition of the symbol, one has to take the following round-about way : Let f be the conductor (Fhrer) of Z,% fp the exact power of p contained in f, and a0 a number in Q with the following properties : * Hasse (12 p. 150).t This follows immediately from the fact that Z is cyclic.X I.e., the conductor of the ideal class group to which Z belongs as class corps (Klassenkrper) See Hasse (7, 9). Hasse (7 Satz 13).Incidentally (3.5) may also be omitted; see Hasse (11, 13 6).I adjoined it here only in order to get a formal simplification in the later proof of Theorem 1, (i).* This alternative form has been introduced by the editors to simplify typography.t See Hasse (7.Erl. 30, 9 8).J See also Dickson (1 51,3 78), Artin (2). See Wedderburn (1), Artin (2).
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