Questão 1207357

σ_{C1 AND C2 AND C3} (R) equivale a σ_C1 (σ_C2 (σ_C3 (R)))

_{C1 AND C2 AND C3} (R) equivale a σ_C1 ( _C2 (σ_C3 (R x R)))

(R θS)θ T equivale a(R ∪ S) Xσ_T (R)))(R)))

(R x S) x T equivale a(T ∪ R) x (R ∪ S) x (T ∪ S)

_{C1 OR C2} (R) equivale a \(\alpha\) _C1 ( _C2 (σ_C1=C2(R)))