Asymptotically equicontinuous sequences of operators and a Banach--Steinhaus type theorem

نویسندگان

1 Département de mathématiques et de statistique, Université Laval, Québec City (Québec), G1V 0A6, Canada.

2 Département de mathématiques et de statistique, Université Laval, Québec City (Québec), G1V 0A6, Canada.

doi
10.30504/jims.2022.361848.1073
چکیده

We introduce the notion of an asymptotically equicontinuous sequence of linear operators, and use it to prove the following result. If $X,Y$ are topological vector spaces, if $T_n,T:X\to Y$ are continuous linear maps, and if $D$ is a dense subset of $X$, then the following statements are equivalent: $(i) ~T_nx\to Tx$ for all $x\in X$, and $(ii) ~T_n x\to Tx$ for all $x\in D$ and the sequence $(T_n)$ is asymptotically equicontinuous.

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