Math 2.0

Real functions Definition

Local minimum

Builds on Local maximum

Definition

Let D⊆ℝD \subseteq \mathbb{R}, let f ⁣:D→ℝf \colon D \to \mathbb{R}, and let a∈Da \in D. The function ff has a local minimum at aa if there is δ>0\delta > 0 with f(x)≥f(a)f(x) \ge f(a) for all x∈Dx \in D with ∣x−a∣<δ|x - a| < \delta. It is a strict local minimum if f(x)>f(a)f(x) > f(a) for all such x≠ax \ne a.

Remarks

So ff has a local minimum at aa exactly when −f-f has a local maximum at aa. For example, x2x^2 has a strict local minimum at 00. Mathlib defines it as IsLocalMin.

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Where this leads

117 pages build on this one.

Further reading

  1. Web https://en.wikipedia.org/wiki/Maximum_and_minimum, Definition
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Tag0NS8BP96QX
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Aliasesrelative-minimum
Kinddefinition
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MSC26A24
DefinesLocal minimum
UsesLocal maximum

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