“…In the same setting, for fixed t > 0, the power variations of x → u(t, x) were discussed in [13,30,41] for p = 2 and in [23] for γ ∈ ( 1 2 , 1] and p = 2/(2γ − 1). In the context of one-parameter stochastic processes, power variations have been investigated for semimartingales [31], fractional Brownian motion and related processes [14,15,36,37,38], and moving average processes [3,4,16], just to name a few.…”