Introduction to sets || Set theory Overview - Part 1

| Set theory | representation of sets | set operations

What is going on in the sewers of New York City? It's a question locals and officials are trying to answer as people have been seen popping in and out of the ground. Williamsburg resident Anthony Purdie said he isn’t convinced it's simple curiosity drawing people to explore the sewers at night. “They look like they were looking for something important, like money, or for doing some type of hurting,” he said. “Ain’t no fun and games. I mean, seven grown adults going down there? Got to be somethin