empty set
Collection without members
The empty set is a set containing no elements—a collection with nothing in it.
In mathematics, it's denoted by ∅ or .
Every set contains the empty set as a subset.
The concept is foundational in set theory and logic: The set of all integers both greater than 5 and less than 3 is the empty set.
Size of a set
- zeroNumerical absence of quantity
- subsetCollection within collection
- intersectionPoint where paths meet
- unionJoining into one
Venn diagram · element · membership · complement · disjoint · Cantor · injection · superset
Without legal effect
- absenceState of not being
- nullityComplete absence or invalidity
- vacuityUtter emptiness or blankness
- nilNothing whatsoever
naught · zero · zilch · nada · bupkis · nothing · nonexistence · hollow
Unmarked mental starting point
- clean slateRecord wiped clear
- blank canvasUntouched painting surface
- fresh startOpportunity to restart unburdened
- unmarkedHaving no visible identification
pristine · unwritten · unused · bare · virgin · starting point · reset · new beginning
cardinality
Size of a set
- zeroNumerical absence of quantity
- subsetCollection within collection
- intersectionPoint where paths meet
union · Venn diagram · element · membership · complement · disjoint · Cantor · injection · superset
void
Without legal effect
nil · naught · zero · zilch · nada · bupkis · nothing · nonexistence · hollow · cipher
tabula rasa
Unmarked mental starting point
- clean slateRecord wiped clear
- blank canvasUntouched painting surface
- fresh startOpportunity to restart unburdened
unmarked · pristine · unwritten · unused · bare · virgin · starting point · reset · new beginning · untouched
- closed setsclosure
- nothingnessnothing, zero, nil, none, nada
- setstool kit, dinnerware, toiletry kit, sewing kit, craft kit
- football playsplay-action pass, slant, counter, draw, sweep
- Nonexistencenothing, nothingness, nonexistence, void, null
- set theorysets, subset, superset, element, union