“…Equation (3) is sometimes called the derivative Swift-Hohenberg equation [37,38]; many papers use a different sign convention for the parameter r (e.g., [27,29,[39][40][41][42][43][44][45] [46] or f 35 = −b 3 φ 4 /4 + φ 6 /6 [19] have also been extensively studied, subject to the conditions b 2 > 27/38 (resp., b 3 > 0) required to guarantee the presence of an interval of coexistence between the homogeneous state φ = 0 and a spatially periodic state. Note that in the context of nonconserved dynamics [19,46] one generally selects a nonlinear term g nl directly, although this term is related to f nl through the relation g nl ≡ −df nl /dφ, i.e., g 23 or g 35 .…”