Questions pertaining to logical constructs

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3
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2answers
1k views

Usage of “if and only if” as a nontechnical term

The phrase "if and only if" (iff) is commonly used in the field of mathematics (⇔) and computer programming, as a conditional expression in classical (Boolean) logic. Within that scope, it might not ...
7
votes
5answers
598 views

Does this logical fallacy have a name?

A phrase being used by the "news" media regarding the recent arrest of people in Columbus, NM is "firearms favored by the Mexican cartels", referring to their purchase of AK47s and other ...
16
votes
7answers
13k views

Does “either A or B ” preclude “both A and B”?

In mathematics, "A or B" includes "A and B". Does "either" mean "A or B but not (A and B)" or does it include the possibility of "A and B"? The context might be mathematics, formal logic or ordinary ...
8
votes
5answers
76k views

“Centered on” or “centered around”

I have often heard presenters talking about something centered around another thing, but it seems a bit illogical and hence improper to talk like this. Am I right about this?
6
votes
6answers
903 views

The word 'not' often doesn't mean total negation in mathematical sense?

Consider the following conversations: X1: I paid $10 for that hamburger. Y1: That's not cheap! X2: I pay $1 for broadband Internet access. Y2: That's cheap! X3: I paid $1 for a hot ...
4
votes
2answers
331 views

Is it true that

Is the following sentence grammatically incorrect? Is it true that 1+1=2 ? I know it is easier to say: Is 1+1=2 true?