Abstract
The cohomology and deformation theory of 3-Lie algebras are revisited. The theory of extending structures and unified product for 3-Lie algebras are developed. It is proved that the extending structures of 3-Lie algebras can be classified by using some non-abelian cohomology and deformation map theory.
Acknowledgments
We would like to thank the referee for careful reading and for valuable suggestions on this paper. Part of this work was done while the author was visiting Courant Research Centre, Georg-August Universität Göttingen from June to September, 2013. He is grateful to Professor Chenchang Zhu for invitation and hospitality.