|
A Representation up to homotopy is a concept in differential geometry that generalizes the notion of representation of a Lie algebra to Lie algebroids and nontrivial vector bundles. It was introduced by Abad and Crainic.〔C.A. Abad, M. Crainic: ''Representations up to homotopy of Lie algebroids'', (arXiv:0901.0319 )〕 As a motivation consider a regular Lie algebroid (''A'',''ρ'',()) (regular meaning that the anchor ''ρ'' has constant rank) where we have two natural ''A''-connections on ''g''(''A'') = ker ''ρ'' and ''ν''(''A'')= ''TM''/im ''ρ'' respectively: : : In the deformation theory of the Lie algebroid ''A'' there is a long exact sequence〔M.Crainic, I.Moerdijk: ''Deformations of Lie brackets: cohomological aspects''. J. Eur. Math. Soc., 10:1037–1059, (2008)〕 : This suggests that the correct cohomology for the deformations (here denoted as ''H''def) comes from the direct sum of the two modules ''g''(''A'') and ''ν''(''A'') and should be called adjoint representation. Note however that in the more general case where ''ρ'' does not have constant rank we cannot easily define the representations ''g''(''A'') and ''ν''(''A''). Instead we should consider the 2-term complex ''A''→''TM'' and a representation on it. This leads to the notion explained here. == Definition == Let (''A'',''ρ'',()) be a Lie algebroid over a smooth manifold ''M'' and let Ω(''A'') denote its Lie algebroid complex. Let further ''E'' be a ℤ-graded vector bundle over ''M'' and Ω(''A'',''E'') = Ω(''A'') ⊗ Γ(''E'') be its ℤ-graded ''A''-cochains with values in ''E''. A representation up to homotopy of ''A'' on ''E'' is a differential operator ''D'' that maps : fulfills the Leibniz rule : and squares to zero, i.e. ''D''2 = 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「Representation up to homotopy」の詳細全文を読む スポンサード リンク
|