All rings throughout this paper are commutative and Noetherian. SEMIDUALIZING MODULES were studied independently by Foxby [4], Golod [5], and Vasconcelos [11]. A finite R-module C is called SEMIDUALIZING if the natural homothety map is an isomorphism and for all . If a SEMIDUALIZING R-module has finite injective dimension, it is called dualizing and is denoted by D. The ring itself is an example of a SEMIDUALIZING R-module. Many researchers, in particular Sather-Wagstaff [12], have studied the SEMIDUALIZING MODULES.
Let M be an R-module. The trace ideal of M, denoted by , is the sum of images of all homomorphisms from M to R. Trace ideals have attracted the attention of many researchers in recent years. In particular, Herzog et al. [6] and Dao et al. [3] studied the trace ideals of canonical MODULES. Also, the trace ideals of SEMIDUALIZING MODULES were studied in [1].
In this paper, we study the trace ideals of tensor product of two arbitrary MODULES. We prove some known facts with a different approach via trace ideals. For example, let C and be two SEMIDUALIZING R-MODULES. We show that is projective if and only if C and are projective R-MODULES of rank 1. Also, we study the trace ideals of maximal Cohen-Macaulay MODULES over a Gorenstein local ring.