Author: Urs Format: MarkdownItexThis is Def. A.10 in
* H. Sati, U. Schreiber, J. Stasheff: _Twisted Differential String and Fivebrane Structures_ ([arXiv:0910.4001](https://arxiv.org/abs/0910.4001), [CMP Vol. 315, Issue 1](https://link.springer.com/article/10.1007%2Fs00220-012-1510-3))