Total Strict Order Relation

From GM-RKB
(Redirected from total order relation)
Jump to navigation Jump to search

A Total Strict Order Relation is a Binary Relation that is a Transitive, a Antisymmetric and a Semiconnex Relation.



References

2020a

  • (Wikipedia, 2020a) ⇒ https://en.wikipedia.org/wiki/Total_order Retrieved:2020-2-15.
    • In mathematics, a total order, simple order, linear order, connex order, or full order is a binary relation on some set [math]\displaystyle{ X }[/math] , which is antisymmetric, transitive, and a connex relation. A set paired with a total order is called a chain,a totally ordered set,a simply ordered set,or a linearly ordered set. Formally, a binary relation [math]\displaystyle{ \leq }[/math] is a total order on a set [math]\displaystyle{ X }[/math] if the following statements hold for all [math]\displaystyle{ a, b }[/math] and [math]\displaystyle{ c }[/math] in [math]\displaystyle{ X }[/math] :
      • Antisymmetry: If [math]\displaystyle{ a \leq b }[/math] and [math]\displaystyle{ b \leq a }[/math] then [math]\displaystyle{ a = b }[/math] ;
      • Transitivity: If [math]\displaystyle{ a \leq b }[/math] and [math]\displaystyle{ b \leq c }[/math] then [math]\displaystyle{ a \leq c }[/math] ;
      • Connexity: [math]\displaystyle{ a \leq b }[/math] or [math]\displaystyle{ b \leq a }[/math] .
(...)

2020b

  • (Wikipedia, 2020b) ⇒ https://en.wikipedia.org/wiki/Total_order#Strict_total_order Retrieved:2020-2-15.
    • For each (non-strict) total order ≤ there is an associated asymmetric (hence irreflexive) transitive semiconnex relation <, called a strict total order or strict semiconnex order,which can be defined in two equivalent ways:
      • a < b if ab and ab
      • a < b if not ba (i.e., < is the inverse of the complement of ≤)
    • Properties:
      • The relation is transitive: a < b and b < c implies a < c.
      • The relation is trichotomous: exactly one of a < b, b < a and a = b is true.
      • The relation is a strict weak order, where the associated equivalence is equality.
    • We can work the other way and start by choosing < as a transitive trichotomous binary relation; then a total order ≤ can be defined in two equivalent ways:
      • ab if a < b or a = b
      • ab if not b < a
    • Two more associated orders are the complements ≥ and >, completing the quadruple {<, >, ≤, ≥}.

      We can define or explain the way a set is totally ordered by any of these four relations; the notation implies whether we are talking about the non-strict or the strict total order.