Will store a list for all of the offers (what is for sale) and all of the bids (What some industry wants to buy). At the end of each day it will be able to find the best match for each offer to the highest bid. When an offer arrives the market will give it a expiration date and an unique number. When the offer expires, the market will find the best bid that it has and match those two together, it will also find the second highest and sell the highest bid for the price of the second highest+1. The bids will have expiration date that the Industries will set on the bids. So bid will be available on the market until it either expires or the market finds a matching offer for it. Market sends information to the buyer and seller to inform them if they have sold or bought something. If there are no bids available for an expiring offer the market should either inform the industry that made that offer that it had expired and no matching bids where found.

Story One

• Each government starts by sending out the rules of how much each Module is allowed to pollute (in form of carbon). They also set the rules of trading between countries and how much they are allowed to produce. The rules for international trading and domestic trading is sent to the market module which enforces the rules.
  
• Each Module receives the information from the government about how much they can pollute. It then has to decide how much of the carbon quota they are going to use. If the governmental rules allow selling carbon between countries then they are allowed to sell to foreigners.
• Trading occurs on the Double Auction Market where the Modules can trade carbon allowances. They can trade between countries only if its Government allows it.
• Demanding/supplies: Each module can send in a demand and it decides how much it is willing to pay for it. The market module keeps track of all the bids and offers that are made and seeks to maximize the number of trades for the bids and offers.
  

Story Two

When the system starts:

• The Government starts by sending to the “Governmental Laws” whiteboard all the rules for each industry modules as a rule about how much each module is allowed to pollute. It also sends the information to the same whiteboard the rules for international and domestic trading. Each of the industry and market module is a subscriber to the “Governmental Laws” to start with. The industry and market modules then subscribe to the “Double Auction Market” whiteboard.
• Each industry module decides if it needs to sell or buy carbon quota. Those trades go through the “Double Auction Market” whiteboard where the market module enforces both the domestic and international trading rules. If one wants to sell then the market module checks whom it is allowed to sell to, and accepts only bids from allowed buyers.
  

This picture is a first draft of the system