-Here is its syntax:
-
-<blockquote>
-<strong>Variables</strong>: <code>x</code>, <code>y</code>, <code>z</code>...
-</blockquote>
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-Each variable is an expression. For any expressions M and N and variable a, the following are also expressions:
-
-<blockquote>
-<strong>Abstract</strong>: <code>(λa M)</code>
-</blockquote>
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-We'll tend to write <code>(λa M)</code> as just `(\a M)`, so we don't have to write out the markup code for the <code>λ</code>. You can yourself write <code>(λa M)</code> or `(\a M)` or `(lambda a M)`.
-
-<blockquote>
-<strong>Application</strong>: <code>(M N)</code>
-</blockquote>
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-Some authors reserve the term "term" for just variables and abstracts. We won't participate in that convention; we'll probably just say "term" and "expression" indiscriminately for expressions of any of these three forms.