trader may contain a clause that arbitration will be in Toronto under Ontarian law with the consequence that the CISG would apply. While a number of States have declared they will not be bound by this condition, Canada has not. The CISG is intended to apply to commercial goods and products only. With some limited exceptions, it does not apply to personal, family, or household goods, nor does it apply to auctions, ships, aircraft, or intangibles and services. The position of computer software is 'controversial' and will depend upon various conditions and situations. Importantly, parties to a contract may exclude or vary the application of the CISG. Under the CISG, an offer to contract must be addressed to a person, be sufficiently definite – that is, describe the goods, quantity, and price – and indicate an intention for the offeror to be bound on acceptance. The CISG does not appear to recognise common law unilateral contracts but, subject to clear indication by the offeror, treats any proposal not addressed to a specific person as only an invitation to make an offer. Further, where there is no explicit price or procedure to implicitly determine price, then the parties are assumed to have agreed upon a price based upon that 'generally charged at the time of the conclusion of the contract for such goods sold under comparable circumstances'. Generally, an offer may be revoked provided the withdrawal reaches the offeree before or at the same time as the offer, or before the offeree has sent an acceptance. Some offers may not be revoked; for example when the offeree reasonably relied upon the offer as being irrevocable. The CISG requires a positive act to indicate acceptance; silence or inactivity are not an acceptance. The CISG attempts to resolve the common situation where an offeree's reply to an offer accepts the original offer, but attempts to change the conditions. The CISG says that any change to the original conditions is a rejection of the offer—it is a counter-offer—unless the modified terms do not materially alter the terms of the offer. Changes to price, payment, quality, quantity, delivery, liability of the parties, and arbitration conditions may all materially alter the terms of the offer. Maritime law Canadian maritime law is a distinct jurisdiction and area of law within the legislative purview of Parliament rather than the provincial legislatures and, as such, is uniform across the