“…The literature on density estimation has steadfastly evolved in response to the growing applications of such techniques. While kernel density estimators prevail as the principal estimation approach, alternatives such as orthogonal sequence estimators have also received appreciable attention, including Schwartz (1967), Watson (1969), Hall (1981), Wahba (1981), and Hall (1987), and more recently Leitao, Oosterlee, Ortiz-Gracia, and Bohte (2018). While orthogonal sequence estimators generally rely on a global basis expansion of the (unknown) density, local density estimators using uniform B-splines and wavelets have also been considered in Redner (1999), Donoho, Johnstone, Kerkyacharian, and Picard (1996), Peter and Rangarajan (2008), Penev and Dechevsky (1997), and Huang (1999).…”