How are fees determined in the Lightning Network? How are fees determined in the Lightning Network?

For transactions that occur on chain, fees are determined by the availability or demand for space in node's mempools. How are they determined in the Lightning Network? 

If there aren't fees in the Lightning Network, what is the economic incentive to operate a node?
Fees are determined by the node operators. It's a free market, you can set whatever fee you want. Of course there's lots of competition, so if you want people to route payments through you, you should set a low or no fee.


  If there aren't fees in the Lightning Network, what is the economic incentive to operate a node?


Even without fees, there is still an incentive to operating a node and using LN. In order to use LN, you must be a node. You will want to use LN to avoid paying higher fees with on chain transactions, and thus you will be operating a LN node.