$w$-singularities in cosmological models

TL;DR

This paper discusses $w$-singularities in cosmological models, showing they are weak singularities where the barotropic index diverges but pressure and density vanish, and compares their strength to other singularities.

Contribution

It analyzes the nature and strength of $w$-singularities, establishing they are weak and comparing them with other cosmological singularities.

Findings

$w$-singularities are weak singularities.

At $w$-singularities, pressure and density vanish.

The singularities are characterized by diverging $w$.

Abstract

Recently a new type of cosmological singularity has been postulated for infinite barotropic index $w$ in the equation of state $p=w \rho$ of the cosmological fluid, but vanishing pressure and density at the singular event. Apparently the barotropic index $w$ would be the only physical quantity to blow up at the singularity. In this talk we would like to discuss the strength of such singularities and compare them with other types. We show that they are weak singularities.