What are the elements?

Question

Rewrite the P by listing it's elements P={y|y is an integer and -4~y<-1}

Answer 1

(...-100,-99,-98...-5,-4,-3,-2]

The elements are all negative integers, except -1. You could put negative infinity as the first "number" as it is not included if you have the open parentheses before it. The bracket at the end indicates -2 is included. Or you could have listed the last element as -1 with another parenthesis to show it is not included.

If you leave out infinity, you could use three periods to indicate all negative integers before -100. You could pick any arbitrary negative number to start after the three periods. Dot dot dot indicates an infinite sequence.

(-infinity....-98,-97,-96...-3,-2,-1)

While y<3, P<-1 If you wanted to list the elements of y, they would be (...-2,-1,0,1, 2, 3) or you could start the sequence of elements with any negative number and put the three periods in front.