Non-regular Lagrangian concordances between Lagrangian fillable Legendrian knots (2509.13594v1)

Abstract: In this short note, we construct a family of non-regular, and therefore non-decomposable, Lagrangian concordances between Lagrangian fillable Legendrian knots in the standard contact 3-dimensional sphere. More precisely, for every decomposable Lagrangian concordance from $\Lambda_-$ to $\Lambda_+$, where $\Lambda_{\pm}$ are smoothly non-isotopic Legendrian knots, we construct a non-regular Lagrangian concordance from $\Lambda'+$ to $\Lambda'-$, where both $\Lambda'\pm$ are Lagrangian fillable Legendrian knots obtained from $\Lambda{\pm}$ by sufficiently many positive and negative stabilisations, followed by a sequence of Legendrian satellite operations.