# Gauge field fluxes and Bianchi identities in extended field theories

## TL;DR

This paper reviews how gauge field fluxes and Bianchi identities in extended field theories relate to brane interactions, tadpole cancellation, and consistency in compactification and cosmological models, through reduction of double field theory.

## Contribution

It provides a detailed analysis of Bianchi identities in extended field theories via reduction of double field theory, connecting to brane interactions and cosmological constraints.

## Key findings

- Bianchi identities can be expressed similarly to Exceptional Field Theory.
- Reduction of double field theory captures all Bianchi identities.
- Framework aids in understanding tadpole cancellation and brane interactions.

## Abstract

Tensor hierarchy of Exceptional Field Theories contains gauge fields satisfying certain Bianchi identities with source part governing interaction with standard and exotic branes. These are responsible for tadpole cancellation in compactification schemes and provide consistency constraints for cosmological model building. Analysis of reduction of (10+10)-dimensional DFT into (D+d+d)-dimensional split DFT allows to consider all Bianchi identities of the theory in the form analogous to the ExFT approach. Here we review in details and elaborate on these ideas.