This is not a question of "solving", but of articulating a sequence a steps that constitute a "proof". In this case "iff" ("if and only if") implies it is a two part proof. The first part is that the condition is necessary for the conclusion to be true. The second part of the proof is that the condition is sufficient for the conclusion to be true. That means there are no other conditions that are needed. How you do such proofs is a matter of experience and this is Homework Help, not homework done for you. show us your best attempt at this two part proof.
Hi @Papabravo . Thanks for your help but I didnt understand what to do. How to show it is satisfy conditions what should I check or which criteria should apply. Can you help me please ?This is not a question of "solving", but of articulating a sequence a steps that constitute a "proof". In this case "iff" ("if and only if") implies it is a two part proof. The first part is that the condition is necessary for the conclusion to be true. The second part of the proof is that the condition is sufficient for the conclusion to be true. That means there are no other conditions that are needed. How you do such proofs is a matter of experience and this is Homework Help, not homework done for you. show us your best attempt at this two part proof.
That is not the direction I would go in. BTW I'm not very intuitive when it comes to constructing mathematical proofs of abstract concepts.normally it should be like Ax=b equations format. Should I apply the closure property to show that it is satisfy the condition?