dex.html"><code>Bastet.String.Monoid</code></a></p><p><code>(^)</code> with <code>&quot;&quot;</code> as the empty element <code>((^), &quot;&quot;)</code>:</p><pre><code class="ml"># let empty = &quot;&quot;;;
val empty : string = &quot;&quot;

# let satisfies_identity_law = &quot;foo&quot; ^ empty = &quot;foo&quot;;;
val satisfies_identity_law : bool = true

# let satisfies_associative_law = &quot;foo&quot; ^ (&quot;bar&quot; ^ &quot;baz&quot;) = (&quot;foo&quot; ^ &quot;bar&quot;) ^ &quot;baz&quot;;;
val