GREENSBORO, N.C. -- The battle over North Carolina's voting districts continued Monday as federal judges heard evidence in a gerrymandering trial that could impact our entire state.

The trial in Greensboro will decide whether lawmakers used illegal, excessive partisanship in 2016 in drawing congressional districts that critics argue gave the Republican party an advantage.

Two expert witnesses were called to the stand on Monday, Dr. Jonathan Christopher Mattingly, a professor of mathematics at Duke and and Dr. Jowei Chen, an associate professor in the political science department at University of Michigan.

Both experts used computer algorithms to map out hypothetical voting districts based on some of the same criteria used by the General Assembly. Each of the experts found that the voting district map used in the 2016 elections and the outcome of the congressional election was extremely rare.

The experts argued that it would be virtually impossible, or at least extremely unlikely, to arrive at the 2016 maps without specifically drawing them to favor Republicans.

The defense argued that some of the evidence being used was not peer-reviewed and had not been published in a journal. They also pointed out that the criteria used in the experts' studies differed from what the General Assembly had been following when they made the maps.

The case continues Tuesday morning in Greensboro.