In a recent Letter Bray and Blythe have shown that the survival probability PA(t) of an A particle diffusing with a diffusion coefficient DA in a 1D system with diffusive traps B is independent of DA in the asymptotic limit t → ∞ and coincides with the survival probability of an immobile target in the presence of diffusive traps. Here we show that this remarkable behavior has a more general range of validity and holds for systems of an arbitrary dimension d, integer or fractal, provided that the traps are "compactly exploring" the space, i.e. the "fractal" dimension dw of traps' trajectories is greater than d. For the marginal case when dw = d, as exemplified here by conventional diffusion in 2D systems, the decay form is determined up to a numerical factor in the characteristic decay time. 02.50Ey, Trapping A+B → B and recombination A+B → 0 reactions (TR and RR) involving randomly moving A and B particles which react "when they meet" at a certain distance b are ubiquitous in nature. A few stray examples include quenching of delocalized excitations, coagulation, recombination of radicals, charge carriers or defects, or biological processes related to population survival [1].In recent years there has been much interest in the long-time behavior of these processes, following a remarkable discovery [2,3,4,5,6,7,8,9,10] of many-particle effects, which induce essential departures from the conventionally expected behavior [1].A pronounced deviation from the text-book predictions was found for the diffusion-controlled RR in case when initially the particles of the A and B species are all distributed at random with strictly equal mean densities n 0 . It has been first shown [2] and subsequently proven [3,4] that as t → ∞ the mean density n(t) follows K S (τ ) being the d-dimensional Smoluchowski-type "constant", defined as the flux of diffusive particles through the surface of an immobile sphere of radius b.For the TR two situations were most thoroughly studied: the case when As diffuse while Bs are static, and the situation in which the As are immobile while Bs diffuse -the so-called target annihilation problem (TAP). In the case of static, randomly placed (with mean density ρ) traps the A particle survival probability P A (t) shows a non-trivial, fluctuation-induced behavior [3,4,5,6,7,8,9,10] lnwhich is intimately related to many fundamenal problems of statistical physics [3,4,5,6,7,8,9,10,11]. Survival probability P target (t) of an immobile target A of radius b in presence of point-like diffusive traps B (TAP) can be calculated exactly for any d (see Refs. [14] and [3,12,13]):where φ On contrary, the physically most important case of TR when both As and Bs diffuse was not solved exactly. It has been proven [4] that here P A (t) obeyswhich equation defines its time-dependence exactly. On the other hand, the factor λ d (D A , D B ) remained as yet an unknown function of the particles' diffusivities and d. Since the time-dependence of the function on the rhs of Eq.(4) follows precisely the behavior of t dτ K S (τ )...