The (+)-(L, P)-TGRS code

The construction of the non-Reed-Solomon (in short, non-RS) type linear code has been one of the research hotspots in recent years. In 2025, Hu et al. constructed some non-RS MDS codes by defining the (L, P)-twisted generalized Reed-Solomon code (in short, (L, P)-TGRS). In this paper, we focus on the (+)-(L, P)-TGRS code C. We firstly present a parity-check matrix. Secondly, we give a sufficient and necessary condition for C to be NMDS which partially answers two open problems proposed by Hu et al. in 2025, and prove that C is non-RS for 2k > n which partially improves the corresponding result given by Hu et al. in 2025,. Thirdly, we give a sufficient condition for C not to be self-dual or self-orthogonal, respectively, furthermore, we construct two classes of self-orthogonal codes which is a promotion of the corresponding result given by Ding et al. in 2025. Finally, some examples are given.