Definition:Therefore/Also known as
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Therefore: Also known as
The symbol $\vdash$ for therefore is sometimes called the turnstile symbol (or gatepost, or gate post), and is often (misleadingly) called the assertion sign.
This is sometimes hyphenated: assertion-sign.
Some older literature uses the symbol $\therefore$ but this is falling out of use.
In contrast to $\vdash$, which is a formal symbol used in proof writing, the $\therefore$ symbol is generally used as shorthand for therefore, and as such is traditionally classified as a punctuation mark.
Also see
- Definition:Because
- Definition:Logical Implication
- Definition:Logical Equivalence
- Definition:Conditional
- Definition:Biconditional
Sources
- 1910: Alfred North Whitehead and Bertrand Russell: Principia Mathematica: Volume $\text { 1 }$ ... (previous) ... (next): Chapter $\text{I}$: Preliminary Explanations of Ideas and Notations
- 1964: Donald Kalish and Richard Montague: Logic: Techniques of Formal Reasoning ... (previous) ... (next): $\text{I}$: 'NOT' and 'IF': $\S 3$
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): assertion sign
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): assertion sign
- 1989: Ephraim J. Borowski and Jonathan M. Borwein: Dictionary of Mathematics ... (previous) ... (next): turnstile or gatepost