Lambda on logos

One use of the lower-case Greek letter λ is a branch of mathematical logic called Lambda Calculus. It’s a formal system designed to research function definition, function application and recursion. Throughout the years, λ has been seen on many logos related with the functional programming. For example, the MIT Scheme’s logo represents a recursive shield with lambda:

We can see lambda on the functional programming language Haskell’s logo. Apart from lambda, we can see five other mathematical symbols, representing the Haskell’s functionality. These are their respective meanings:

-The right arrow (→): Transformation
-The universal quantification (∀): For all
-The double angle (≫): Free from disorder
-The double right arrow (⇒): Generality
-The double colon (::): Exactitude

A scheme-to-C compiler called Chicken has a logo that represents a lambda inside a hen silhouette.

CL-HTTP (Common Lisp Hypermedia Server) has a lambda symbol on its logo too.

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