7.1 The basics

Overview

You don't need to learn a whole lot about lambda expressions, even though much could be said. Therefore, we will just give some examples and a little explanation.

Where to get advanced information

If you want to know more, you are encouraged to read through this series of pages.

Introduction by means of an example

A lambda expression could look like this:

   [Person: ?x]<-(Agnt)<-[Sing]
   "A person, x, is singing"

Note the occurrence of '?x' in the space of the referent of the "Person" concept. This syntactic construct, '?x', is a placeholder for something else. We can fill this slot with the referent of another concept, as we shall see shortly.

Why is it called a 'lambda-expression'?

The reason this is called a lambda expression is that traditionally, such placeholders are written using the Greek letter lambda, or . Thus the above graph could be written:

   [Person: ]<-(Agnt)<-[Sing]
   "A person, , is singing"

We will mostly stick to the other notation, where we use ?x, ?y, ?z, ?a, ?b, etc. instead of , 1, 2, 3, 4, etc.

Monadic, dyadic, triadic, n-adic

A lambda expression can be monadic, as in the example above, where there is only one formal parameter. A lambda expression can also be dyadic or triadic, having two or three formal parameters respectively. In general, a lambda expressions can have n formal parameters and be n-adic.