"is true" and "can be true"
In most cases, simple "equal to" or "unequal to" relations would suffice in order to establish or evaluate logical statuses such as e.g. "Error = No" and in the case of conditions viewpoints "is true" or "is not true" are sufficient.
Sometimes, however, also more complex relational operators are necessary; that is why LF‑ET evaluates a logical expression as successfully checked not only if it "is true" but also if it "can be true":
Example 1
Expression |
Processing or evaluation successful? |
|
|---|---|---|
Set A = B |
yes |
direct determination of a new condition: A equals B |
A < B |
no |
A cannot be smaller than B |
A <= B |
yes |
this expression is also true if A equals B |
A = B |
yes |
corresponds to the saved relation |
A <> B |
no |
A cannot be unequal to B |
A >= B |
yes |
this expression is also true if A equals B |
A > B |
no |
A cannot be greater than B |
Example 2
Expression |
Processing or evaluation successful? |
|
|---|---|---|
Set A < B |
yes |
direct determination of a new condition: A smaller than B |
A < B |
yes |
corresponds to the saved relation |
A <= B |
yes |
this expression is also true if A is smaller than B |
A = B |
no |
A cannot be equal to B |
A <> B |
yes |
this expression is also true if A is smaller than B |
A >= B |
no |
A cannot be greater than or equal to B |
A > B |
no |
A cannot be greater than B |
Example 3
Expression |
Processing or evaluation successful? |
|
|---|---|---|
Set A <= B |
yes |
direct determination of a new condition: A smaller than OR equal to B |
A < B |
yes |
this expression is also true if A is smaller than B |
A <= B |
yes |
corresponds to the saved relation |
A = B |
yes |
this expression is also true if A equals B |
A <> B |
yes |
this expression is also true if A is smaller than B |
A >= B |
yes |
this expression is also true if A equals B |
A > B |
no |
A cannot be greater than B |