Discrete maths

Predicate to mathematical logic

where universe for x and y are the students in the MA5801 class. Write the following sentences in terms of these predicates (Note: You may introduce the predicates x = y or x y if required).

(a) Susan has received an email from David

(b) Jeff has never telephoned Mal

(c) Everyone in the class called Russel or sent him an email.

(d) Nobody in the class emailed himself/herself.