Ivanov's asphericity conjecture

Let

$$\mathcal{P}=[ x_1,x_2,\ldots,x_n\mid r_1,r_2,\ldots,r_m]$$

be an aspherical presentation. Let

$$\mathcal{Q}=[ x_1,x_2,\ldots,x_n,x\mid r_1,r_2,\ldots,r_m,r]$$

be a presentation such that the total exponent of $x$ in $r$ is nonzero, the group $H$ presented by $\mathcal{P}$ naturally embeds in the group $G$ presented by $\mathcal{Q}$, and $G$ is torsion-free.

Ivanov's asphericity conjecture. Then $\mathcal{Q}$ is aspherical.

The conjecture is refuted: Ivanov showed that a counterexample would provide a torsion-free group whose integral group ring contains zero divisors, while the supplied status evidence records the conjecture as disproved.