I am currently reading about monoidal categories in the book "Tensor categories" and I am confused about the following: The authors write that the functors $L_1: X \mapsto 1 \otimes X$ and $R_1: X \mapsto X \otimes 1$ are autoequivalences of $C$. My question is
What does it mean that $R_1$ and $L_1$ are autoequivalences ?
Can someone give me some explanations ?
Thanks for your help.