1、Positive semi-definite matrices are positive definite if and only if they are nonsingular.
2、An epistemic proposition is true if and only if it is a member of corresponding world.
3、A good deductive argument is sound if and only if it's both valid and has true premises.
4、It is proved that a triangular norm is left-continuous if and only if is increasing union-preserving, and is right-continuous if and only if is decreasing intersection-preserving.
5、Hashes of two sets of data should match if and only if the corresponding data also matches.
6、A rational decisionmaker takes an action if and only if the marginal benefit of the action exceeds the marginal cost.
7、A wordis valid if and only if each ordered pair of adjacent letters inthe word is a valid pair.
8、Eye of newt goes into the little black bag, if and only if there isreproducible scientific evidence that it works.
9、That is, society will reward you with a remarkable life if and only if you can offer in return a useful and rare service.
10、At least 3 times in the body content (more or less depending on amount of content and if and only if it makes sense).
11、The fact is that your potential is unlimited if and only if you believe and you act towards drawing on it.
12、Then T is an invertible linear operator preserving rank - partial ordering on Sn(F) if and only if there exists an invertible matrix (F) such that where .
13、"Logicians distinguish two main types of implication, material and strict. Proposition p materially implies proposition q if and only if the material conditional p e q (read "if p then q") is true"
14、Whenever you hear the word if, then, and, or, not, if and only if, all these logical words, all, is, lovely logical words, you've got to be sensitized this week because I want to hear you.
15、If a project has a unique IRR, we can state that the project increases the value of the company if and only if the project's IRR exceeds the annual cost of capital.
16、And the reason for that because an argument is valid if and only if there are no possible situation in which all its premises are true and its conclusion false.
