a$.$ What does True and False means as atom sentences in context of first order logic?

b$.$ What is the formal definition of entailment?

c$.$ Is $\backslash$alpha valid if True $|=\backslash$alpha $?$

d$.$ Does for any $\backslash$alpha $,$ False $|=\backslash$alpha $?$

e$.$ Is $\backslash$alpha $|=\backslash$beta valid if the sentence $(\backslash$alpha $\backslash$beta $)$ is valid?

f$.$ Is $\backslash$alpha $\backslash$beta valid if and only if the sentence $(\backslash$alpha $\backslash$beta $)$ is valid?

g$.$ Is $\backslash$alpha $|=\backslash$beta if the sentence $(\backslash$alpha $\backslash$beta $)$ is unsatisfiable?