The drift operator Δ_t on a recognition fiber H_t is a monotone endomorphism that moves recognitions along a temporal or dynamical axis: it models how semantic values shift or evolve at a given trace. Unlike the stabilizer σ_t, drift is not required to be idempotent — applying drift repeatedly may continue to shift recognitions.
Drift commutes with the stabilizer: Δ_t ∘ σ_t = σ_t ∘ Δ_t. This commutation is one of the central structural requirements of the GFRTU, ensuring that the two dynamics (consolidation and evolution) are compatible. A recognition is dynamically stable when it is fixed by both operators: the fixed fiber H_t* = {a : σ_t(a) = a = Δ_t(a)}.
Drift in the GFRTU plays a role analogous to the temporal trace comonad G in the semiotic universe: both model temporal or dynamical evolution of semantic values. The interaction axiom j(G(a)) ≤ G(j(a)) in the semiotic universe mirrors the commutation of stabilizer and drift in the GFRTU, ensuring that modal and temporal structure remain coherent.