Chapter 1 - Foundations of Geometry

Front

set

Back

collection of objects,

set A = {1, 2, 4}

Front

Element

Back

an object in a set

Jack ∈ A

Joy ∉ A

Front

empty or null set

Back

a set containing no elements, denoted ∅ or { }

Front

subset

Back

Every element of A is also in B, denoted A ⊆ B, A could also be equal to B

Front

Proper Subset

Back

B is a subset of A, but B is not equal to A

B ⊂ A

Front

equivalent sets

Back

sets with the same number of elements, denoted E ∼ F or E ≡ F

Front

disjoint sets

Back

sets that have no elements in common

Front

universal set

Back

a set that contains all the elements in the context of a given problem, denoted U

Front

union

Back

denoted A ∪ B, the set combining all the elements of the given sets

Front

intersection

Back

denoted A ∩ B, the set containing the elements common to both sets, the overlap