The Issue "Think about a relation R with five characteristics ABCDE. You're because of the following dependancies

- A->B
- BC->E
- Erectile dysfunction->A

List all of the secrets for R.

The teacher gave us the secrets, That are ACD,BCD,CDE

And we have to show the job to get at them.

~~The Very First two I solved.~~

~~For BCD, the transitive of two with 3 to obtain (BC->E)D->A => BCD->A.~~
~~as well as for ACD id the the transitive of just one with 4 (BCD), to obtain (A->B)Compact disc->A => ACD->A~~

~~However I can't learn how to get CDE.~~

Therefore it appears Used to do it wrong, after searching I discovered this answer

- methodology to locate secrets: consider attribute sets α that contains: a. the determinant characteristics of F (i.e. A, BC, Erectile dysfunction) and b. the characteristics NOT included in the determined ones (i.e. C,D). Then perform the attribute closure formula: if α+ superset R then α -> R Three secrets: CDE, ACD, BCD Source

From what I will tell, since C,D are this is not on the left side from the dependencies. The secrets remain sides with Compact disc pre-appended for them. Can anybody explain this in my experience in better detail why?

To obtain they **secrets**, starting with **among the dependencies** and taking advantage of inference to increase the set.

Allow me to try it out with simple British, you'll find formal definition the internet easily.

e.g. begin with 3).

```
ED -> A
```

(knowing E and D, I understand A)

```
ED ->AB
```

(knowing E and D, I understand A, by knowing A, I understand B too)

```
ED->AB
```

Still, C can't be known, and I have tried personally all of the rules now except BC->E, And So I add C left hands side, i.e.

```
CDE ->AB
```

so, **by knowing C,D and E**, you will be aware **A** and **B** too,
Hence **CDE is really a key for the relation ABCDE**. You repeat exactly the same process, beginning along with other rules until exhausted.