Приклади вживання Propositional function Англійська мовою та їх переклад на Українською
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A quantified propositional function is a statement;
A set of logical connectives associated with a formal systemis functionally complete if it can express all propositional functions.
Note that a quantified propositional function is a statement;
If you say“There is a universe,” that meaning of“there is” will be quite different from the meaning in which yousay“There is a particular,” which means that“the propositional function‘x is a particular' is sometimes true.”.
You want to say of a propositional function that it is sometimes true.
The element c must be completely arbitrary; else, the logic does not follow: if c is not arbitrary, and is instead a specific element of the universe of discourse, then P(c)only implies an existential quantification of the propositional function.
It expresses that a propositional function can be satisfied by every member of a domain of discourse.
So that you arrive at the fact that the ultimate important notion involved in existence is the notion that I developed in the lecture before last,the notion of a propositional function being sometimes true, or being, in other words, possible.
Sometimes, P(x) is also called a propositional function, as each choice of x produces a proposition.
We mean partly that we do not know whether it will rain or whether it will not, but also that we do know that that is the sort of proposition that is quite apt to be true,that it is a value of a propositional function of which we know some value to be true.
We say of a propositional function that it is possible, where there are cases in which it is true.
Sometimes, P(x) is also called a(template in the role of) propositional function, as each choice of the placeholder x produces a proposition.
For example, if P(x) is the propositional function"x is greater than 0 and less than 1", then, for a domain of discourse X of all natural numbers, the existential quantification"There exists a natural number x which is greater than 0 and less than 1" is symbolically stated:.
All the things you want to say about classesare the same as the things you want to say about propositional functions excepting for accidental and irrelevant linguistic forms, with, however, a certain proviso which must now be explained.
When I say a propositional function is possible, meaning there are cases in which it is true, I am consciously using the word“possible” in an unusual sense, because I want a single word for my fundamental idea, and cannot find any word in ordinary language that expresses what I mean.
Universal generalization concludes the propositional function must be universally true if it is true for any arbitrary element of the universe of discourse.
A quantified propositional function is a statement; thus, like statements, quantified functions can be negated.
There are a certain number of things which you can say about a propositional function which would not be true if you substitute another formally equivalent propositional function for it.
On the other hand, any statement about a propositional function which will remain true or remain false, as the case may be, when you substitute for it another formally equivalent propositional function, maybe regarded as being about the class which is associated with the propositional function. .
Universal instantiation concludes that, if the propositional function is known to be universally true, then it must be true for any arbitrary element of the universe of discourse.
For instance, the propositional function“x is a man” is one which has to do with the concept of humanity.
You mean simply that the propositional function“x is a color between blue and yellow” is one which is capable of truth.
For example, if P(x) is the propositional function"x is married", then, for a universe of discourse X of all living human beings, the universal quantification.
Note that a quantified propositional function is a statement; thus, like statements, quantified functions can be negated.
Generally, then, the negation of a propositional function's existential quantification is a universal quantification of that propositional function's negation; symbolically.
Some of the things that you can say about a propositional function will not necessarily remain true if you substitute another formally equivalent propositional function in its place.
Existential introduction(∃I) concludes that, if the propositional function is known to be true for a particular element of the domain of discourse, then it must be true that there exists an element for which the proposition function is true.
A valuation is a function that assigns each propositional variable either T(for truth) or F(for falsity).
A valuation is a function that assigns each propositional variable either T(for truth) or F(for falsity).