The principles of law and equity, including the law of corporations and unincorporated associations and limited liability companies, the law of real property and the law relative to capacity to contract, principal and agent, eminent domain, estoppel, fraud, misrepresentation, duress, coercion, mistake, receivership, substantial performance, or other validating or invalidating cause supplement this part and parts 3-5 of this chapter, except to the extent inconsistent with this part and parts 3-5 of this chapter.