Below is an example which shows Entailment using language of logic and connectives.
| A | B | A -> B |
|---|---|---|
| T | T | T |
| T | F | F |
| F | T | T |
| F | F | T |
Given A -> B is true. Then new table looks like,
| A | B | A -> B |
|---|---|---|
| T | T | T |
| F | T | T |
| F | F | T |
Given A is true. Then new table is,
| A | B | A -> B |
|---|---|---|
| T | T | T |
So, B is necessarily be true.
We can say that, A and A -> B entail B.