<?php
  $foo = array(1,2,3,4,5);
  if(in_array(array(2,3), $foo)) echo "foo";

  $foo = array(1,2,3,4,5, array(2,3));
  if(in_array(array(2,3), $foo)) echo "bar";

  $foo = array(1,2,3,4,5, array(2,3,4));
  if(in_array(array(2,3), $foo)) echo "baz";

bar