Examine the following formal descriptions of sets so that you understand which members they contain. Write a short informal English description of each set.

a. {1, 3, 5, 7, . . . }

b. { ..., -4, -2, 0, 2, 4, . . . }

c. {n| n = 2rn for some m in N}

d. {n| n = 2m for some m in N, and n = 3k for some k in N}

e. {w| w is a string of Os and is and w equals the reverse of w}

f. {n| n is an integer and n = n + 1}