Ultrafilters is an English word. Below you'll find 10+ example sentences showing how it's used in practice.
Ultrafilters meaning
plural of ultrafilter
Using Ultrafilters
- The main meaning on this page is: plural of ultrafilter
- In the example corpus, ultrafilters often appears in combinations such as: all ultrafilters, ultrafilters on, of ultrafilters.
Context around Ultrafilters
- Average sentence length in these examples: 21.5 words
- Position in the sentence: 5 start, 2 middle, 4 end
- Sentence types: 11 statements, 0 questions, 0 exclamations
Corpus analysis for Ultrafilters
- In this selection, "ultrafilters" usually appears near the start of the sentence. The average example has 21.5 words, and this corpus slice is mostly made up of statements.
- Around the word, using, powerset, free, alternatively and turns stand out and add context to how "ultrafilters" is used.
- Recognizable usage signals include 1 of ultrafilters turns out and construction using ultrafilters alternatively if. That gives this page its own corpus information beyond isolated example sentences.
- By corpus frequency, "ultrafilters" sits close to words such as aab, aamer and aave, which helps place it inside the broader word index.
Example types with ultrafilters
The same corpus examples are grouped by length and sentence type, making it easier to see the contexts in which the word appears:
Proofs involving the axiom of choice do not produce explicit examples of free ultrafilters. (14 words)
The ultraproduct construction in model theory uses ultrafilters to produce elementary extensions of structures. (14 words)
Saharon Shelah later showed that it is consistent that there are no P-point ultrafilters. (15 words)
For ultrafilters on a powerset ℘(S), a principal ultrafilter consists of all subsets of S that contain a given element s of S. Each ultrafilter on ℘(S) that is also a principal filter is of this form. (37 words)
The set G of all ultrafilters of a poset P can be topologized in a natural way, that is in fact closely related to the above-mentioned representation theorem. (29 words)
Construction using ultrafilters Alternatively, if X is discrete, one can construct βX as the set of all ultrafilters on X, with a topology known as Stone topology. (27 words)
Example sentences (11)
Construction using ultrafilters Alternatively, if X is discrete, one can construct βX as the set of all ultrafilters on X, with a topology known as Stone topology.
An ultrafilter on ℘(ω) is Ramsey if and only if it is minimal in the Rudin–Keisler ordering of non-principal powerset ultrafilters.
For ultrafilters on a powerset ℘(S), a principal ultrafilter consists of all subsets of S that contain a given element s of S. Each ultrafilter on ℘(S) that is also a principal filter is of this form.
It can be proven by bisection method used in proving the Bolzano-Weierstrass theorem, the property (1) of ultrafilters turns out to be crucial.
Proofs involving the axiom of choice do not produce explicit examples of free ultrafilters.
Saharon Shelah later showed that it is consistent that there are no P-point ultrafilters.
Such ultrafilters are called trivial, and if we use it in our construction, we come back to the ordinary real numbers.
The set G of all ultrafilters of a poset P can be topologized in a natural way, that is in fact closely related to the above-mentioned representation theorem.
The ultraproduct construction in model theory uses ultrafilters to produce elementary extensions of structures.
Types and existence of ultrafilters There are two very different types of ultrafilter: principal and free.
Ultrafilters can alternatively be described as 2-valued morphisms from A to the two-element Boolean algebra.
Common combinations with ultrafilters
These word pairs occur most frequently in English texts:
- all ultrafilters 2×
- ultrafilters on 2×
- of ultrafilters 2×