I can't answer your question, but I stumbled upon such concept while reading the MIT news. If you're interested, the professor Bradford Skow has recently publis

I can't answer your question, but I stumbled upon such concept while reading the MIT news. If you're interested, the professor Bradford Skow has recently published a book on the subject: http://goo.gl/L9538k http://goo.gl/L9538k.