Consider the following premises. w <-> p. r -> w. w -> p. p -> r. Can we infer w <-> r from them?
 From w <-> p we can infer p -> w. From w -> p, p -> w we can infer w <-> p. From w <-> p we can infer w -> p. From w -> p, p -> r we can infer w -> r. Finally, from w -> r, r -> w we can infer w <-> r. Therefore, the answer is yes.