Extension of the homotopy Maurer–Cartan framework to 3-gauge theories

Extend the homotopy Maurer–Cartan framework developed for balanced 2-term $L_\infty$-algebras to 3-gauge theories described by 2-crossed modules and related strict higher-gauge models, including the construction of appropriate higher invariant polynomials and invariant forms for the associated 3-term $L_\infty$-algebraic data.

Background

The paper constructs semistrict higher Chern–Simons theories in dimensions $2n+2$ from balanced 2-term LL_\infty-algebras, using higher invariant multilinear forms, higher Pontryagin–Chern forms, transgression formulas, and the extended Cartan homotopy formula. The authors identify an unresolved extension of this framework to the next level of higher gauge theory, namely 3-gauge theories governed by 2-crossed modules and related strict models.

Solving this problem would require developing suitable higher invariant polynomials and corresponding invariant differential forms for 3-term LL_\infty-algebraic structures, thereby extending the paper’s construction beyond semistrict Lie 2-algebras.

References

Several natural directions remain open for future investigation. It is natural to ask whether the homotopy MC framework used in this paper admits an extension to $3$-gauge theories described by $2$-crossed modules and related models of strict higher gauge theory . Such a generalization would require the construction of appropriate higher invariant polynomials and the corresponding invariant forms for the associated $3$-term $L_\infty$-algebraic data.

Higher Chern--Simons Theory in $2n+2$ Dimensions for Balanced 2-term $L_\infty$-Algebras  (2608.19539 - Song et al., 20 Aug 2026) in Section 7, Conclusion and outlook