Darboux's law of intermediate values

E904573

Darboux's law of intermediate values is a fundamental theorem in real analysis stating that the image of a continuous function on an interval contains every value between any two of its function values.

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Predicate Object
instanceOf mathematical theorem
result in real analysis
alsoKnownAs Darboux property
Darboux's theorem (real analysis)
appliesTo continuous functions with values in R
functions defined on intervals of the real line
real-valued functions
assumes domain is an interval in R
function is continuous on the interval
characterizes the image of a continuous function on an interval as connected
conclusion the range of the function on the interval is an interval
contrastsWith behavior of discontinuous functions that may have jump discontinuities
coreStatement If f is continuous on an interval I and a,b are in I, then for every value y between f(a) and f(b) there exists c in I between a and b such that f(c)=y.
The image of a continuous function on an interval is an interval.
ensures no jump discontinuities for continuous functions on intervals
field real analysis
formalizes intuitive idea that graphs of continuous functions on intervals have no gaps in their vertical values
generalizationOf the idea that continuous functions on intervals cannot skip values
hasProperty does not require differentiability
non-constructive in typical proofs
historicalPeriod 19th-century mathematics
holdsIn standard real number system R
implies continuous real functions on intervals have the intermediate value property
images of intervals under continuous maps are intervals
intermediate value property for continuous functions
importance basic tool in elementary real analysis
fundamental theorem in the foundations of calculus
involves intervals of real numbers
order topology on R
mathematicalDomain analysis
namedAfter Jean Gaston Darboux
relatedConcept Darboux functions
connectedness of subsets of R
continuity
intermediate value property
relatedTo Bolzano's theorem
existence of roots of continuous functions on intervals
intermediate value theorem
requires completeness of the real numbers for standard proofs
order structure of the real numbers
topicOf university-level analysis courses
usedIn proofs of the intermediate value theorem
real analysis textbooks
theory of differential equations
topology of the real line
usedToShow existence of solutions to equations f(x)=y for intermediate values y

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Referenced by (7)

Full triples — surface form annotated when it differs from this entity's canonical label.

Johannes G. G. Darboux notableWork Darboux's law of intermediate values
Johannes G. G. Darboux knownFor Darboux's law of intermediate values
Johannes G. G. Darboux hasNotableConceptNamedAfter Darboux's law of intermediate values
Bernard Bolzano notableIdea Bolzano’s theorem on continuous functions
linked to: Darboux's law of intermediate values
Darboux's law of intermediate values alsoKnownAs Darboux's theorem (real analysis)
linked to: Darboux's law of intermediate values
Darboux's law of intermediate values alsoKnownAs Darboux property
linked to: Darboux's law of intermediate values
Darboux's law of intermediate values relatedConcept Darboux functions
linked to: Darboux's law of intermediate values