@article{oai:soar-ir.repo.nii.ac.jp:00019329,
 author = {Kuribayashi, Katsuhiko},
 issue = {2},
 journal = {Homology, Homotopy and Applications},
 month = {},
 note = {We establish equalities between cochain and chain type levels of maps by making use of exact functors which connect appropriate derived and coderived categories. Relevant conditions for levels of maps to be finite are extracted from the equalities which we call duality on the levels. Moreover, we give a lower bound of the cochain type level of the diagonal map on the classifying space of a  Lie group by considering the ghostness of a shriek map which appears in derived string topology. A variant of Koszul duality for a differential graded algebra is also discussed., Article, Homology, Homotopy and Applications. 18(2):107-132 (2016)},
 pages = {107--132},
 title = {The ghost length and duality between chain and cochain type levels},
 volume = {18},
 year = {2016}
}