Comparing Finite-Time Lyapunov Exponents and Lagrangian Descriptors for identifying phase space structures in a simple two-dimensional, time-periodic double-gyre model

I could not retrieve or search the uploaded paper via the file_search tool (no searchable content returned), so I cannot audit or cite the paper’s statements. The candidate (model) solution appears largely consistent with standard local hyperbolic linearization heuristics for FTLE/LD in the double-gyre and with common qualitative claims (FTLE-ridge non-materiality; LD kinks across invariant manifolds; small FTLE on KAM tori; LD’s single-trajectory computation), but several steps rely on unverified assumptions (e.g., use of instantaneous stagnation points vs. hyperbolic trajectories; ridge–manifold identification without variational LCS conditions). Without access to the paper’s arguments, I cannot reconcile or adjudicate correctness.