In mathematics, the tombstone, halmos, end-of-proof, or Q.E.D. symbol "∎" (or "□") is a symbol used to denote the end of a proof, in place of the traditional abbreviation "Q.E.D." for the Latin phrase " quod erat demonstrandum". It is inspired by the typographic practice of end marks, an element that marks the end of an article. ^{[1] [2]}

In Unicode, it is represented as character U+220E ∎ END OF PROOF. Its graphic form varies, as it may be a hollow or filled rectangle or square.

In AMS-LaTeX, the symbol is automatically appended at the end of a proof environment \begin{proof} ... \end{proof}. It can also be obtained from the commands \qedsymbol, \qedhere or \qed (the latter causes the symbol to be right aligned). ^[3]

It is sometimes called a "Halmos finality symbol" or "halmos" after the mathematician Paul Halmos, who first used it in a mathematical context in 1950. ^[4] He got the idea of using it from seeing end marks in magazines, that is, typographic signs that indicate the end of an article. In his memoir I Want to Be a Mathematician, he wrote the following: ^[1]

The symbol is definitely not my invention — it appeared in popular magazines (not mathematical ones) before I adopted it, but, once again, I seem to have introduced it into mathematics. It is the symbol that sometimes looks like ▯, and is used to indicate an end, usually the end of a proof. It is most frequently called the 'tombstone', but at least one generous author referred to it as the 'halmos'.

See also

• -30-
• Block Elements
• End-of-file
• End-of-Transmission character
• Therefore sign (∴)

Notes

References

• Miller, Jeff (September 29, 2007), Earliest Uses of Symbols of Set Theory and Logic, retrieved June 26, 2010

This typography-related article is a stub. You can help Wikipedia by expanding it.

• v
• t
• e