For those reading the paper: the positives of a good-view JEPA are described as “two observations of one scene,” and yet the paper also states that “A good-view JEPA's positives are (g_m(z, ν), g_m(z′, ν′)) with (z, z′) ∼ π and independent nuisances.” My question is: why doesn't “two observations of one scene” mean that both observations share the same underlying world state (z) and differ only in their modality nuisances (ν and ν′)? Also, I don't understand what “a symmetric positive-pair distribution (z, z′) ∼ π_m” (or more explicitly, a “world kernel”) means.