ISSUE-68: New proposal

There is a new proposal to create a formal definition of pre-binding 
based on a draft that Andy has prepared for the SPARQL EXISTS CG.

PROPOSAL: Close ISSUE-68 defining pre-binding using eval(D(G), 
Replace(PrjMap(X), μ) as described 
inhttps://w3c.github.io/sparql-exists/docs/sparql-exists.html

Please add your comments to

https://www.w3.org/2014/data-shapes/wiki/Proposals#ISSUE-68:_Definition_of_Pre-Binding

Regards,
Holger