Dual

wikipedia

In maths, a concepts dual is a 1-1 relationship between that concept and another. It is sometimes an inversion. So $A \rightarrow B$'s dual might be $A \leftarrow B$. This is quite a general idea though - it's effectively a two-way relationship between two concepts.

Examples

• Set Theory: the empty set and the singleton set

Backlinks

• The singleton set
  • Its dual is the empty set.
• Unit Type
  • It is related to the singleton set from set theory and dual to the void type
• Void Type
  • It's dual is the unit type. It corresponds to the empty set from set theory.

Backlinks

• The singleton set
  • Its dual is the empty set.
• Void Type
  • In type theory, the void type is a type with a cardinality of $0$. It is therefore impossible to construct. It's dual is the unit type. It corresponds to the empty set from set theory.
• Dual
  • It's dual is the unit type. It corresponds to the empty set from set theory.
• Unit Type
  • It is related to the singleton set from set theory and dual to the void type