Question

Given L(R,F,C) where R={P,Q}, F={f,g}, C={a,b} and the set of variables is {x,y,z}, which of the following are sentences of L(R,F,C)?
P(a,b) ∧ ∃x∀y(Q(x,a) ν Q(x,z))
∀z(P(a,b) ∧ ∃x∀y(Q(x,a) ν Q(x,z)))
P(Q(a),b) ∧ ∃x∀y(Q(x,y) ν Q(x,c))
∀x(P(a,b) ∧ ∃x∀y(Q(x,a) ν Q(x,z)))

Answer 1

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