I have defined a similarity measure $U_{sim}(T_t,T_{t-1})$ which is the similarity metric between two items. Now I wanna show the the similarity between $T_t$ and all previous $T_i$s. I represented like this:
$$\bigcup^{t-1}_{i=1}U_{sim}(T_t,T_i)$$
in which the output is a set of real values. Is this correct?
What other notations normally is used in mathematics for similarity? I did not know that is why I showed with $U_{sim}$