#66 Cannot create new markets

[Anonymous]

Hi Chris,

I am having trouble creating a new market (in the PM framework). I create the first market fine, but when trying to create a 2nd market (using the 'create markets' button) it drives me back to the previously crated market. I tried closing the first market, but that doesn't change the behaviour. The log file throws:
04/18 10:09:15.772/CDT WARN - UserError - 94# told user1 "A market with the name 'Market1' already exists.".
04/18 10:09:15.798/CDT WARN - UserError - 95# told user1 "market is closed.".

Is this a bug? or normal behaviour

[Chris Hibbert]

Did you use a different name for the second market? That error message is supposed to be produced when a new market is requested and it has the same name as a market that already exists.

[Anonymous]

Chris, I don't seem to be able to reproduce the problem.
The problem was that once a user created a new market, she was not able to create a second market. It didn't even showed me the createMarkets.jsp page, the 'create markets' button ported me back to the purchaseClaim.jsp instead.

I can't reproduce this behavior I was having. And things are back to normal.

However, I do have another concern. Zocalo uses the logarithmic rule to generate prices, right? Is this model a case of (i) short sale, (ii) basket of goods or (iii) complementary assets?

I'm asking because I'd like my students to start playing with a multi-outcome market generated with a market maker but I haven't been able to explain them how to use the 'quantity' and 'price' cells in purchaseClaim.jsp. As I interpret it 'quantity' as the number of positions to sell of a certain position and the 'price' cell would become irrelevant (because price is fixed by the exponential rule). Is this interpretation correct?

If this is the case I wouldn't let the price cell to be filled by users, but leave it as an information cell.

[Chris Hibbert]

> Zocalo uses the logarithmic rule to generate prices, right? Is this model
> a case of (i) short sale, (ii) basket of goods or (iii) complementary assets?

If you choose to have a market have an automated market maker, then the market maker will use the logarithmic rule.

The model is complementary assets whether we're talking about binary or n-way markets. Each trader spends money to buy assets that have a (positive) conditional value.

> I haven't been able to explain them how to use the 'quantity' and 'price' cells in
> purchaseClaim.jsp. As I interpret it 'quantity' as the number of positions
> to sell of a certain position and the 'price' cell would become irrelevant
> (because price is fixed by the exponential rule). Is this interpretation
> correct?

Both price and quantity are limits on the max that will be purchased. The idea is that you can specify either a quantity or a price limit. The quantity is the max that you want to purchase. If you don't fill in a price limit, you'll buy the max quantity if you can afford it.

Alternatively, you can specify the price target. "I want to move the price to x". In the latter case, you might want to limit the quantity you buy so you don't spend your whole balance on one trade.

For instance, you'd like to buy some shares, and think 100 shares would be about right. The current price is .4, you think it should be higher, but you don't think the price should be higher than .8. So you can set a price limit so you won't move the price beyond .8.

Another choice is to change the useCostLimit configuration parameter. Rather than limiting purchases according to the resulting price of the asset, traders limit their purchases according to the max they're willing to spend.