基本介紹
- 中文名:直積
- 外文名:direct product
- 別稱:笛卡爾乘積
- 提出者:笛卡爾
- 所屬學科:數理科學
- 舉例:群的直積、拓撲空間的直積等
直積簡介
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不同種類的直積
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直積亦稱“笛卡兒積”,集的重要運算之一。設a、b為兩個集,則有序偶〈x,y〉(x∈a,y∈b)的全體也構成一個集,稱為a、b的直積,用a×b表示。...
直積映射(direct product mapping)一種特殊的映射,即由若干個映射導出的,定義在它們的定義域的直積上的映射。[1] 中文名 直積映射 外文名 direct product mapp...
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維數直積定理(Cartesian product theorem ofdimension)關於維數的一組定理: 1.若X ,Y為可分可度量化空間,則 ind (XXY)鎮ind X十ind Y. 這是門傑(Menger,...
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∏是希臘字母,即π的大寫形式,在數學中表示求積運算或直積運算,形式上類似於Σ。...... ∏是希臘字母,即π的大寫形式,在數學中表示求積運算或直積運算,形式上類...
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定義 中心積(central product)直積的一種推廣.設H和K是群G的子群,若H和K的元素可換,且G=HK,則稱CT為H,K的中心積.當H(}K={1}時,中心積即為直積. ...
一般,B基於A的擴張不是唯一的,例如,A與B的直積A×B是B基於A的一個擴張,而A與B的半直積也是B基於A的擴張。所謂A與B的半直積為G,是指G=AB,AG,且A∩...
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叫做集合X,Y(按順序)的直積或笛卡爾積,X×X叫做X^2。 集合中的對角線: △ = {(a,b)∈X^2| a = b } 是X^2的一個子集,它給出集X中元素的相等...