example of knowledge representation logic

Logic is a form of knowledge representation of the oldest. This representation  type uses the expressions in formal logic to represent the knowledge base. Basically the logic is the process of forming conclusions and draw an inference based on the fact that already exist. Input from the process logic a premise or the facts admitted the truth so that by doing logical process of reasoning can be formed on an inference or conclusion that true as well.
Examples of the simple fact that we will represent the logic is as follows:

Helder is a dog
Facts in English they will be represented in logic, namely:
dogs (Helder)
We can also represent another logical facts, namely that all
dogs have tails
x: dog (x)
caudate (x)
Then deductively (reasoning starts from the general principles for get a more specific conclusion) of the mechanism of  this logic we can obtain a new representation:
caudate (dog)
By using the mapping function is backward, we can download the generate sentences in English
Helder caudate