Chapter 2.5, Problem 26E

To determine

(a)

To explain:

$F\subseteq N$ is the set of all factors of 210 in the poset $(F,|)$ then need invention to $30\wedge 21$, which meet of $30$ and $21$.

To determine

(b)

To explain:

$F\subseteq N$ is the set of all factors of 210 in the poset $(F,|)$ then need invention to $35\vee 15$, which meet of $35$ and $15$.

To determine

(c)

To explain:

$F\subseteq N$ is the set of all factors of 210 in the poset $(F,|)$ then need invention to $2\wedge 7$.

To determine

(d)

To explain:

$F\subseteq N$ is the set of all factors of 210 in the poset $(F,|)$ then need invention to $2\vee 7$.

To determine

(e)

To explain:

$F\subseteq N$ is the set of all factors of 210 in the poset $(F,|)$ then need invention to $\neg 30$, the complement of $30$.