Communicating Sequential Processes
f a i l u r e s ( ( a → S T O P ) ◻ ( b → S T O P ) ) = { ( ⟨ ⟩ , ∅ ) , ( ⟨ a ⟩ , { a , b } ) , ( ⟨ b ⟩ , { a , b } ) } {\displaystyle failures\left(\left(a\rightarrow STOP\right)\Box \left(b\rightarrow STOP\right)\right)=\left\{\left(\langle \rangle ,\emptyset \right),\left(\langle a\rangle ,\left\{a,b\right\}\right),\left(\langle b\rangle ,\left\{a,b\right\}\right)\right\}} f a i l u r e s ( ( a → S T O P ) ⊓ ( b → S T O P ) ) = { ( ⟨ ⟩ , { a } ) , ( ⟨ ⟩ , { b } ) , ( ⟨ a ⟩ , { a , b } ) , ( ⟨ b ⟩ , { a , b } ) } {\displaystyle failures\left(\left(a\rightarrow STOP\right)\sqcap \left(b\rightarrow STOP\right)\right)=\left\{\left(\langle \rangle ,\left\{a\right\}\right),\left(\langle \rangle ,\left\{b\right\}\right),\left(\langle a\rangle ,\left\{a,b\right\}\right),\left(\langle b\rangle ,\left\{a,b\right\}\right)\right\}}