Universality conjecture for leading-order small-maturity forward smile asymptotics

Consider the stochastic-volatility model given by equation, and let the forward-start date and the time to maturity tend to the small-maturity regime considered in Corollary~. The leading-order small-maturity forward smile asymptotics are the asymptotic expansion of the forward implied volatility smile at that order.

Universality conjecture. The leading-order small-maturity forward smile asymptotics generated from the stochastic-volatility model given by equation are equivalent to those given in Corollary~.

The conjecture asserts that the leading-order forward smile explosion is determined by the variance distribution at the forward-start date rather than by the detailed dynamics of the stock price. The surrounding discussion compares this behavior with the Heston model when $p=1/2$, but the supplied text gives no resolution of the conjecture.