Projective and injective objects in symmetric categorical groups

Abstract

We prove that the 2-category of symmetric categorical groups have enough projective and injective objects. This was conjectured by Bourn and Vitale in 2002 and was anounced recently by Fang Huang, Shao-Han Chen, Wei Chen and Zhu-Jun Zheng in arXiv:1006.4677 with wrong proof.

References in corpus (3)

• Third Mac Lane cohomology via categorical rings
• Enrichments over symmetric Picard categories
• Higher Dimensional Homology Algebra II:Projectivity

Cited by in corpus (2)

• On abelian 2-categories and derived 2-functors
• Higher Dimensional Homology Algebra III:Projective Resolutions and Derived 2-Functors in (2-SGp)