 The classical formula by Dupire, despite being heavily used by industry practitioners , can potentially produce unstable or even singular volatility surfaces ] . In this paper, we propose a new local volatility calibration technique using the theory of optimal transport.
<meaning-changed>  The classical formula by Dupire, despite being heavily used by industry practitioners , can potentially produce unstable or even singular volatility surfaces ] . In this paper, we propose a new local volatility calibration technique using the theory of optimal transport.
 The classical formula by Dupire, despite being heavily used by industry practitioners , can potentially produce unstable or even singular volatility surfaces 6] . In this paper, we propose a new local volatility calibration technique using the theory of optimal transport.