Stochastic Collocation - Old And New

Thomas Roos recently put a preprint on SSRN called Simple, Flexible, Analytic, Arbitrage Free Volatility Interpolation. Being interested in the subject, I had a detailed look at it. It turns out that Thomas stumbled upon spline stochastic collocation without realizing it. There are a few differences in his approach: The optimization is on the x’s instead of the y’s, meaning the strike axis is fixed. An original approach to avoid spurious modes, although I would have liked more detail