Mathematical Logic
| Sign | Example | Name | Meaning and verbal equivalent | Remarks |
|---|---|---|---|---|
| ∧ | p ∧ q | conjunction sign | p and q | |
| ∨ | p ∨ q | disjunction sign | p or q (or both) | |
| ¬ | ¬ p | negation sign | negation of p; not p; non p | |
| ⇒ | p ⇒ q | implication sign | if p then q; p implies q | Can also be written as q ⇐ p. Sometimes → is used. |
| ∀ | ∀x∈A p(x) (∀x∈A) p(x) |
universal quantifier | for every x belonging to A, the proposition p(x) is true | The "∈A" can be dropped where A is clear from context. |
| ∃ | ∃x∈A p(x) (∃x∈A) p(x) |
existential quantifier | there exists an x belonging to A for which the proposition p(x) is true | The "∈A" can be dropped where A is clear from context. ∃! is used where exactly one x exists for which p(x) is true. |
Read more about this topic: ISO 31-11
Famous quotes containing the words mathematical and/or logic:
“It is by a mathematical point only that we are wise, as the sailor or the fugitive slave keeps the polestar in his eye; but that is sufficient guidance for all our life. We may not arrive at our port within a calculable period, but we would preserve the true course.”
—Henry David Thoreau (1817–1862)
““... We need the interruption of the night
To ease attention off when overtight,
To break our logic in too long a flight,
And ask us if our premises are right.””
—Robert Frost (1874–1963)