element
any one of the distinct objects that make up a set in set theory
discontinuity
point at which a function is not continuous
zero element
one of several generalizations of the number zero to other algebraic structures
integral element
Mathematical element
index
the numbering of various objects within the mathematical notation
irreducible element
non-zero non-unit element in an integral domain that is not a product of two non-units
object of a category
constituent element of the mathematical notion of category
Borel set
set that can be constructed from open or closed sets by repeatedly taking countable unions and intersections
Coxeter element
concept in geometry
ideal point
point at infinity in hyperbolic geometry
commutator
notion in ring theory
absolutely integrable function
function whose absolute value has finite integral
boundary point
point on the boundary of a set