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In algebraic geometry, a logarithmic pair consists of a variety, together with a divisor along which one allows mild logarithmic singularities. They were studied by . ==Definition== A boundary Q-divisor on a variety is a Q-divisor ''D'' of the form Σ''d''''i''''D''''i'' where the ''D''''i'' are the distinct irreducible components of ''D'' and all coefficients are rational numbers with 0≤''d''''i''≤1. A logarithmic pair, or log pair for short, is a pair (''X'',''D'') consisting of a normal variety ''X'' and a boundary Q-divisor ''D''. The log canonical divisor of a log pair (''X'',''D'') is ''K''+''D'' where ''K'' is the canonical divisor of ''X''. A logarithmic 1-form on a log pair (''X'',''D'') is allowed to have logarithmic singularities of the form d log(''z'') = d''z''/''z'' along components of the divisor given locally by ''z''=0. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「logarithmic pair」の詳細全文を読む スポンサード リンク
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