Lambda

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Lambda (uppercase Λ, lowercase λ; Λάμβδα or Λάμδα, lamda or lamtha) is the 11th letter of the Greek alphabet. In the system of Greek numerals lambda has a value of 30. Lambda is related to the Phoenician letter Lamed Image:Phoenician lamedh.png. Letters in other alphabets that stemmed from lambda include the Roman L and the Cyrillic letter El (Л, л). The ancient grammarians and dramatists give evidence to the pronunciation as laːbdaː (λάβδα) in Classical Greek times.[1] In Modern Greek the name of the letter, Λάμδα, is pronounced lamða; the spoken letter itself has the sound of [l] as with Latinate "L".

In early Greek alphabets, the shape and orientation of lambda varied.[2] Most variants consisted of two straight strokes, one longer than the other, connected at their ends. The angle might be in the upper left, lower left ("Western" alphabets), or top ("Eastern" alphabets). Other variants had a vertical line with a horizontal or sloped stroke running to the right. With the general adoption of the Ionic alphabet, Greek settled on an angle at the top; the Romans, borrowing from Western alphabets, put the angle at the lower left.

Contents

Symbol

Upper-case letter Λ

Lower-case letter λ

Lower-case lambda
Lower-case lambda

Lambda, the word

  • In programming languages such as Lisp and Python, lambda is an operator used to denote anonymous functions or closures, following the usage of lambda calculus. An example of this use of lambda in the Python language is this section of computer code that sorts a list alphabetically by the last character of each entry:

<source lang="python">>>> list = ['woman', 'man', 'horse', 'boat', 'plane', 'dog'] >>> sorted(list, key=lambda word: word[-1]) ['horse', 'plane', 'dog', 'woman', 'man', 'boat']</source>

  • In the C# programming language a lambda expression is an anonymous function that can contain expressions and statements.[5]
  • The language Unlambda is a functional programming language based upon combinatory logic, a simplification of the lambda calculus that does not involve the lambda at all, hence the un- prefix.
  • An automotive oxygen sensor (O2 sensor) is also known as a lambda probe, sensor, sond, or sonde.
  • Lambda is used in art and photography to refer to a digital Type C print, or to the equipment that is used to produce it.
  • Lambda was used by Pythagoras to denote the "Lambda number sequence" { 1, 2, 3, 4, 8, 9, 27, ... }

Lambda as a name

A capital Lambda
A capital Lambda
  • Stargate SG-1 uses a modified upper-case lambda, with a small circle above the apex, to indicate Earth. This symbol has since become associated with the entire franchise.[7][8]

See also

References

Majuscule form
ΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΩ
Minuscule form
αβγδεζηθικλμνξοπρστυφχψω
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