dellintervallo

Dell'intervallo is the standard Italian expression meaning "of the interval." It is a genitive construction used to indicate that a property, element, or quantity pertains to a specific interval, commonly denoted by [a,b] or (a,b). The phrase is not a separate mathematical object; it is a grammatical device that accompanies nouns such as valore, elemento, estremità, or lunghezza.

The correct spelling in standard Italian is dell'intervallo, formed from di + l'intervallo. The form dellintervallo (without an apostrophe) is generally considered nonstandard in formal writing, though it may appear in informal text or as a variable name in programming contexts, where rule-based orthography is often relaxed.

In mathematical usage, dell'intervallo occurs to qualify statements about a particular interval. Examples include: i membri dell'intervallo [a,b], le estremità dell'intervallo, la lunghezza dell'intervallo, o il valore dell'intervallo quando si discute di proprietà di x per x nell'intervallo. The phrase helps situate definitions, bounds, and measurements within the context of the chosen interval.

See also: Intervallo, Intervallo aperto, Intervallo chiuso, Estremo di un intervallo.

References: standard Italian mathematical terminology in dictionaries and textbooks would cover the use of dell'intervallo in phrases describing domains and ranges.