Is there a common mathematical symbology for collections? Preface: So, it was suggested in 'Programmers' that I ask this over here.

I am being asked to define several of my algorithms in mathematical terms to describe my work to a customer. I trying to determine if anybody knows whether common operators for collections like sequences, lists, tuples, etc have been defined. If so, is there a good reference that I could be pointed to. Thanks. I am interested in the actual symbols used. I am wondering if the following would make sense or be appropiate to anybody.

Given two sequences (or strings):

S = (A, B, C) and T = (A, D, H)

In my mind, the intersection of these sequences would look like S ∩ T = (A) and the union of these sequences would be S ∪ T = (A, B, C, A, D, H)
Specification languages such as Z have a vast range of data types and operations on them and, at least within that community, these are standardised. This tutorial gives a great overview. Other specification languages exist, such as B and Alloy which may also satisfy your requirements.