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Glossary

Sign Vector

A sign vector on a finite ground set $$E is a vector in $\{-,+,0\}$E.

For example, $$X = (+,0,+,-) is a sign vector on a ground set of cardinality $4$, say $$E = {1,2,3,4}.
Usually, we simply write $$X = (+0+-) or $$X = +0+-.

The sign corresponding to an element $$e in E is denoted by $$X_e.