It's called dumping. You have artificially low costs temporarily in order to put competitors out of business. Once that's achieved, you then increase prices.
I'm actually not sure how dumping would work when done by Uber, though. Individual taxi drivers will go out of business, but there's little barriers to entry to new taxi drivers starting out again once Uber starts to flex its pricing power. Of course the picture changes if Uber starts to lobby for regulatory protection. You have to look at the micro details of the market to see whether there's a problem there.
I'm actually not sure how dumping would work when done by Uber, though. Individual taxi drivers will go out of business, but there's little barriers to entry to new taxi drivers starting out again once Uber starts to flex its pricing power. Of course the picture changes if Uber starts to lobby for regulatory protection. You have to look at the micro details of the market to see whether there's a problem there.