At the biggest tech antitrust trial in decades, the government alleged Tuesday that Google feeds a cycle that pumps its profits while preventing rivals from gaining market share.

The 10-week trial against Google began Tuesday in Washington, D.C. District Court with lawyers from the Justice Department and a coalition of state attorneys general led by Colorado. During the first day of the trial, the government and Google argued their opposing views of how Google has maintained a large share of the search market for many years.

By creating strong barriers to entry and a feedback loop, Google has maintained its dominance of the general search market, according to the government.

According to Google, it is simply the preferred choice of consumers. Through revenue-sharing agreements, browser makers and phone manufacturers chose Google as their default search engine because of its popularity.

Each side also outlined who would be relying on to support their arguments in the opening statements. Aside from economic experts, Google said the court would hear from its own executives and those from other companies about its level of dominance and behavior.

The DOJ’s lawyer said Google intends to call company CEO Sundar Pichai to testify in court. Google’s lawyer said the panel will also hear from Apple’s senior vice president of services, Eddy Cue, and Mozilla’s CEO, Mitchell Baker. A number of other Google executives, including those who oversee advertising services and search products, are also expected to testify.