# c-extremization from toric geometry

## TL;DR

This paper presents a geometric approach to calculating the 2d central charge in theories derived from 4d superconformal field theories, linking it to toric diagram areas and exploring the relation between 4d a-maximization and 2d c-extremization.

## Contribution

It introduces a geometric formulation of the 2d central charge using toric geometry, connecting 4d and 2d extremization principles in superconformal theories.

## Key findings

- Central charge expressed via toric diagram areas.
- Relation established between 4d a-maximization and 2d c-extremization.
- Applicable to both smooth and singular toric geometries.

## Abstract

We derive a geometric formulation of the 2d central charge $c_r$ from infinite families of 4d $\mathcal{N}=1$ superconformal field theories topologically twisted on constant curvature Riemann surfaces. They correspond to toric quiver gauge theories and are associated to D3 branes probing five dimensional Sasaki-Einstein geometries in the AdS/CFT correspondence. We show that $c_r$ can be expressed in terms of the areas of the toric diagram describing the moduli space of the 4d theory, both for toric geometries with smooth and singular horizons. We also study the relation between a-maximization in 4d and c-extremization in 2d, giving further evidences of the mixing of the baryonic symmetries with the exact R-current in two dimensions.