https://www.reuters.com/article/us-tech-antitrust-bigtech-factbox/big-techs-market-dominance-spurs-numerous-u-s-antitrust-probes-idUSKBN2751TK >The U.S. Justice Department is expected to file a lawsuit against Alphabet Inc's Google on Tuesday in what could be just the first in a series of legal salvos against high-profile tech companies.