# Descending wedge

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The descending wedge symbol may represent:

The vertically reflected symbol, ∧, is a wedge, and often denotes related or dual operators.

The ∨ symbol was introduced by Russell and Whitehead in Principia Mathematica, where they called it the Logical Sum or Disjunctive Function.[1]

In Unicode the symbol is encoded U+2228 LOGICAL OR (&or;, &vee;). In TeX, it is `\vee` or `\lor`.

One motivation and the most probable explanation for the choice of the symbol ∨ is the latin word "vel" meaning "or" in the inclusive sense. Several authors use "vel" as name of the "or" function.[2][3][4][5][6][7][8][9]

## References

1. ^ Whitehead, Alfred North (2005). Principia mathematica, by Alfred North Whitehead ... and Bertrand Russell.
2. ^ Rueff, Marcel; Jeger, Max (1970). Sets and Boolean Algebra. American Elsevier Publishing Company. ISBN 978-0-444-19751-1.
3. ^ Trappl, Robert (1975). Progress in Cybernetics and Systems Research. Hemisphere Publishing Corporation. ISBN 978-0-89116-240-7.
4. ^ Constable, Robert L. (1986). Implementing Mathematics with the Nuprl Proof Development System. Prentice-Hall. ISBN 978-0-13-451832-9.
5. ^ Malatesta, Michele (1997). The Primary Logic: Instruments for a Dialogue Between the Two Cultures. Gracewing Publishing. ISBN 978-0-85244-499-3.
6. ^ Harris, John W.; Stöcker, Horst (1998-07-23). Handbook of Mathematics and Computational Science. Springer Science & Business Media. ISBN 978-0-387-94746-4.
7. ^ Tidman, Paul; Kahane, Howard (2003). Logic and Philosophy: A Modern Introduction. Wadsworth/Thomson Learning. ISBN 978-0-534-56172-7.
8. ^ Kudryavtsev, Valery B.; Rosenberg, Ivo G. (2006-01-18). Structural Theory of Automata, Semigroups, and Universal Algebra: Proceedings of the NATO Advanced Study Institute on Structural Theory of Automata, Semigroups and Universal Algebra, Montreal, Quebec, Canada, 7-18 July 2003. Springer Science & Business Media. ISBN 978-1-4020-3817-4.
9. ^ Denecke, Klaus; Wismath, Shelly L. (2009). Universal Algebra and Coalgebra. World Scientific. ISBN 978-981-283-745-5.