Chapter 1.5, Problem 5E

Let W(x,y) mean that studentxhas visited websitey, where the domain forxconsists of all students in your school and the domain foryconsists of al websites. Express each of these statements by a simple English sentence.

a) $W\left(\text{Sarah}\text{Smith,}\text{www}\text{.att}\text{.com}\right)$

b) $\exists xW\left(x,\text{www}\text{.imbd}\text{.com}\right)$

c) $\exists yW\left(\text{Jose}\text{Orez},y\right)$

d) $\exists y\left(W\left(\text{Ashok}\text{Puri},y\right)\wedge W\left(\text{Cindy}\text{yoon},y\right)\right)$

e) $\exists y\forall z\left(y\ne \left(\text{David}\text{Belcher}\right)\wedge \left(W\left(\text{David}\text{Belcher},z\right)\to W\left(y,z\right)\right)\right)$

f) $\exists x\exists y\forall z\left(\left(x\ne y\right)\wedge \left(W\left(x,z\right)\right)\leftrightarrow W\left(y,z\right)\right)$