Definition:Minimal Element/Comparison with Smallest Element

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Definition

Compare the definition of minimal element with that of a smallest element.


Consider the ordered set $\struct {S, \preceq}$ such that $T \subseteq S$.

An element $x \in T$ is the smallest element of $T$ if and only if:

$\forall y \in T: x \preceq y$

That is, $x$ is comparable with, and precedes, or is equal to, every $y \in T$.


An element $x \in T$ is a minimal element of $T$ if and only if:

$y \preceq x \implies x = y$

That is, $x$ precedes, or is equal to, every $y \in T$ which is comparable with $x$.

If all elements are comparable with $x$, then such a minimal element is indeed the smallest element.


Note that when an ordered set is in fact a totally ordered set, the terms minimal element and smallest element are equivalent.


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