The Gleason-Kahane-Żelazko theorem and its generalizations
نویسندگان
چکیده
منابع مشابه
Gleason-kahane-Żelazko theorem for spectrally bounded algebra
We prove by elementary methods the following generalization of a theorem due to Gleason, Kahane, and Żelazko. Let A be a real algebra with unit 1 such that the spectrum of every element in A is bounded and let φ : A→ C be a linear map such that φ(1) = 1 and (φ(a))2 + (φ(b))2 = 0 for all a, b in A satisfying ab = ba and a2 + b2 is invertible. Then φ(ab) = φ(a)φ(b) for all a, b in A. Similar resu...
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ژورنال
عنوان ژورنال: Banach Center Publications
سال: 1994
ISSN: 0137-6934,1730-6299
DOI: 10.4064/-30-1-327-331