Google RDFa breadcrumbs

Question

I am currently trying to implement RDFa breadcrumbs to my webpages. I think that I am following the example for multiple breadcrumbs on one page correctly, however in the testing tool and search results the breadcrumbs are not processed as expected (are extracted, but the breadcrumbs are not displayed).

Can you plese give me a hint what am I doing wrong.

Thanks.

Page with the breadcrumbs

<div class="breadCrumb">
    <span typeof="v:Breadcrumb">
        <a href="/" ref="v:url" property="v:title">Algoritmy.net</a> &gt; 
        <span rel="v:child">
             <span typeof="v:Breadcrumb">
                 <a ref="v:url" property="v:title" href="/category/39974/Mathematics">Mathematics</a> &gt; 
                 <span rel="v:child">
                     <span typeof="v:Breadcrumb">
                         <a ref="v:url" property="v:title" href="/category/48669/Primality">Primality</a> &gt; 
                         <span rel="v:child">
                              <span typeof="v:Breadcrumb">
                                  <a href="/article/47455/Rabin-Miller-test" ref="v:url" property="v:title">Rabin-Miller test</a>
                              </span>
                         </span>
                     </span>
                 </span>
            </span>
        </span>
    </span>
</div>

Answer 1

"ref" isn't a valid RDFa or HTML attribute, make sure you spell it right: rel. ref="v:url" should be rel="v:url"