Difference between revisions of "Topology of compact convergence"
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+ | One of the topologies on a space of continuous functions; the same as the [[Compact-open topology|compact-open topology]]. For the space of linear mappings $ L( E, F ) $ | ||
+ | from a locally convex space $ E $ | ||
+ | into a locally convex space $ F $, | ||
+ | the topology of compact convergence is one of the $ \sigma $- | ||
+ | topologies, i.e. a topology of uniform convergence on sets belonging to a family $ \sigma $ | ||
+ | of bounded sets in $ E $; | ||
+ | it is compatible with the vector space structure of $ L( E, F ) $ | ||
+ | and it is locally convex. | ||
====Comments==== | ====Comments==== | ||
− | Thus, the topology of compact convergence on | + | Thus, the topology of compact convergence on $ L( E, F ) $ |
+ | is defined by the family of all compact sets, [[#References|[a1]]]. | ||
− | The topology of pre-compact convergence is the | + | The topology of pre-compact convergence is the $ \sigma $- |
+ | topology defined by the family of all pre-compact sets, [[#References|[a2]]]. | ||
− | The topology of compact convergence in all derivatives in the space | + | The topology of compact convergence in all derivatives in the space $ C ^ {m} ( \mathbf R ^ {n} ) $ |
+ | of all $ m $ | ||
+ | times differentiable real- or complex-valued functions on $ \mathbf R ^ {n} $ | ||
+ | is defined by the family of pseudo-norms | ||
− | + | $$ | |
+ | \{ {q _ {K} ^ {(} m) } : {K \subset \mathbf R ^ {n} \textrm{ compact } } \} | ||
+ | , | ||
+ | $$ | ||
− | + | $$ | |
+ | q _ {K} ^ {(} m) ( f ) = \sup \{ | D ^ {p} f( x) | : x \in K, | p | \leq m \} . | ||
+ | $$ | ||
The resulting space of functions is locally convex and metrizable, [[#References|[a3]]]. | The resulting space of functions is locally convex and metrizable, [[#References|[a3]]]. |
Latest revision as of 08:26, 6 June 2020
One of the topologies on a space of continuous functions; the same as the compact-open topology. For the space of linear mappings $ L( E, F ) $
from a locally convex space $ E $
into a locally convex space $ F $,
the topology of compact convergence is one of the $ \sigma $-
topologies, i.e. a topology of uniform convergence on sets belonging to a family $ \sigma $
of bounded sets in $ E $;
it is compatible with the vector space structure of $ L( E, F ) $
and it is locally convex.
Comments
Thus, the topology of compact convergence on $ L( E, F ) $ is defined by the family of all compact sets, [a1].
The topology of pre-compact convergence is the $ \sigma $- topology defined by the family of all pre-compact sets, [a2].
The topology of compact convergence in all derivatives in the space $ C ^ {m} ( \mathbf R ^ {n} ) $ of all $ m $ times differentiable real- or complex-valued functions on $ \mathbf R ^ {n} $ is defined by the family of pseudo-norms
$$ \{ {q _ {K} ^ {(} m) } : {K \subset \mathbf R ^ {n} \textrm{ compact } } \} , $$
$$ q _ {K} ^ {(} m) ( f ) = \sup \{ | D ^ {p} f( x) | : x \in K, | p | \leq m \} . $$
The resulting space of functions is locally convex and metrizable, [a3].
References
[a1] | F. Trèves, "Topological vectorspaces, distributions and kernels" , Acad. Press (1967) pp. 198 |
[a2] | G. Köthe, "Topological vector spaces" , 1 , Springer (1969) pp. 263ff |
[a3] | J.L. Kelley, I. Namioka, "Linear topological spaces" , v. Nostrand (1963) pp. 82 |
Topology of compact convergence. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Topology_of_compact_convergence&oldid=48991