I do not have a background in mathematics. However, I do empirical research and I oftentimes have difficulties finding the correct mathematical notations for certain things I want to express:
I am comparing two sets of values. Each value in one set relates to a certain value in the other set, i.e. the two sets represent a set of "pairs". How do I express that, e.g. more than half of the values in one set are larger than their respective counterpart in the other set?
Let the two sets be $A$ and $B$; the wording implies that they are finite. You say that all the elements can be paired, so there is a bijective function $f:A\mapsto B$ expressing this relation. Call the cardinality of each set $n$.
Your last sentence may then be written as $$|\{a\in A:a>f(a)\}|>\frac n2$$