@unpublished{ Li.Nakatsukasa.Soma.ea:2017, author = {Zhening Li and Yuji Nakatsukasa and Tasuku Soma and Andr{\'e} Uschmajew}, title = {On orthogonal tensors and best rank-one approximation ratio}, year = {2017}, month = {jul}, annote = {preprint}, note = {INS Preprint No. 1707}, inspreprintnum= {1707}, eprint = {1707.02569}, archiveprefix = "arXiv" }