Math and science::Analysis
18 analysis theorems
The following propositions about an ordered field
- 1. The Dedekind Completeness Property (Supremum)
- Suppose
is a nonempty subset of that is bounded above. Then there exists a number that is an upper bound of such that every upper bound of is greater than or equal to .
We refer to this as completeness. - 2. The Archimedean Property
-
For every
there exists with . Equivalently, for every there exists with .
Doesn't imply completeness. - 3. The Cut Property
- Suppose
and are nonempty disjoint subsets of whose union is all of , such that every element of is less than every element of . Then there exists a cutpoint such that every is in and every is in . (Or, if you prefer: Every is , and every is . It's easy to check that the two versions are equivalent.) Since this property may be unfamiliar, we remark that the Cut Property follows immediately from Dedekind completeness (take to be the least upper bound of ).
Does imply completeness. - 4. Topological Connectedness
-
Say
is open if for every in there exists so that every with is also in . Then there is no way to express as a union of two disjoint nonempty open sets. That is, if with nonempty and open, then is nonempty.
Does imply completeness. - 5. The Intermediate Value Property
-
If
is a continuous function from to , with and , then [...].
[Does/doesn't imply completeness?] - 6. The Bounded Value Property
-
If
is a continuous function from to , then [...].
[Does/doesn't imply completeness?] - 7. The Extreme Value Property
-
If
is a continuous function from to , then [...].
[Does/doesn't imply completeness?] - 8. The Mean Value Property
-
Suppose
is continuous on and differentiable on . Then [...].
[Does/doesn't imply completeness?] - 9. The Constant Value Property
-
Suppose
is continuous on and differentiable on , with for all in . Then [...].
[Does/doesn't imply completeness?] - 10. The Convergence of Bounded Monotone Sequences
-
[The title gives this one away.]
[Does/doesn't imply completeness?] - 11. The Convergence of Cauchy Sequences
-
[And this one]
[Does/doesn't imply completeness?] - 12. The Fixed Point Property for Closed Bounded Intervals
-
Suppose
is a continuous map from to itself. Then [...].
[Does/doesn't imply completeness?] - 13. The Contraction Map Property
-
Suppose
is a map from to itself such that for some constant , for all . Then [...].
[Does/doesn't imply completeness?] - 14. The Alternating Series Test
-
If
and , then converges.
Doesn't imply completeness. - 15. The Absolute Convergence Property
-
If
converges in , then converges in .
Doesn't imply completeness. - 16. The Ratio Test
-
If
in as , with , then converges in .
Does imply completeness. - 17. The Shrinking Interval Property
-
Suppose
are bounded closed intervals in with lengths decreasing to 0. Then the intersection of the 's is nonempty.
Doesn't imply completeness. - 18. The Nested Interval Property
-
Suppose
are bounded closed intervals in . Then the intersection of the 's is nonempty. (Another name for this property is "spherical completeness''.)
Doesn't imply completeness.