equitable distribution

New york is equitable distribution state, meaning that there is no automatic 1/2 division of marital asset, unlike those in community property state (CA, NM, MI etc. formerly Spanish or French colonies that follows continental rule).  

In any case, 1/2 of appreciated value during marriage (婚後房子增值的一半) is a good starting point for negotiation.  

Equitable distribution are not based on 1/2 formular, but factors see this link

http://www.jdbar.com/Statutes/DRL-236-B/drl-236-b.html#5?