Generalized Ordinary Differential Equations in Abstract Spaces and Applications. Группа авторов

Чтение книги онлайн.

Читать онлайн книгу Generalized Ordinary Differential Equations in Abstract Spaces and Applications - Группа авторов страница 21

Generalized Ordinary Differential Equations in Abstract Spaces and Applications - Группа авторов

Скачать книгу

alt="parallel-to f Subscript n Baseline left-parenthesis t 0 plus delta right-parenthesis minus f 0 left-parenthesis t 0 plus delta right-parenthesis parallel-to less-than epsilon and parallel-to f Subscript n Baseline left-parenthesis t 0 Superscript minus Baseline right-parenthesis minus f 0 left-parenthesis t 0 Superscript minus Baseline right-parenthesis parallel-to less-than epsilon period"/>

      When t element-of left-bracket a comma b right-bracket satisfies t 0 minus delta less-than-or-slanted-equals t less-than t 0, we have, for every n greater-than-or-slanted-equals n 0,

parallel-to f Subscript n Baseline left-parenthesis t 0 Superscript minus Baseline right-parenthesis minus f Subscript n Baseline left-parenthesis t right-parenthesis parallel-to less-than-or-slanted-equals parallel-to f Subscript n Baseline left-parenthesis t 0 Superscript minus Baseline right-parenthesis minus f 0 left-parenthesis t 0 Superscript minus Baseline right-parenthesis parallel-to plus parallel-to f 0 left-parenthesis t 0 Superscript minus Baseline right-parenthesis minus f 0 left-parenthesis t right-parenthesis parallel-to plus parallel-to f 0 left-parenthesis t right-parenthesis minus f Subscript n Baseline left-parenthesis t right-parenthesis parallel-to less-than 3 epsilon period parallel-to f Subscript n Baseline left-parenthesis t right-parenthesis minus f Subscript n Baseline left-parenthesis t 0 Superscript plus Baseline right-parenthesis parallel-to less-than-or-slanted-equals parallel-to f Subscript n Baseline left-parenthesis t right-parenthesis minus f 0 left-parenthesis t right-parenthesis parallel-to plus parallel-to f 0 left-parenthesis t right-parenthesis minus f 0 left-parenthesis t 0 Superscript plus Baseline right-parenthesis parallel-to plus parallel-to f Subscript n Baseline left-parenthesis t 0 Superscript plus Baseline right-parenthesis minus f 0 left-parenthesis t 0 Superscript plus Baseline right-parenthesis parallel-to less-than 3 epsilon period

      But this yields the fact that left-brace f Subscript n Baseline right-brace Subscript n element-of double-struck upper N is an equiregulated sequence, and the proof is complete.

      The next lemma guarantees that, if a sequence of functions left-brace f Subscript k Baseline right-brace Subscript k element-of double-struck upper N is bounded by an equiregulated sequence of functions, then left-brace f Subscript k Baseline right-brace Subscript k element-of double-struck upper N is also equiregulated.

      Lemma 1.15: Let be a sequence of functions in . Suppose, for each , the function satisfies

       for every , where for each and the sequence is equiregulated. Then, the sequence is equiregulated.

      A clear outcome of Lemmas 1.13 and 1.15 follows below:

      

      Corollary 1.16: Let be a sequence of functions from to and suppose the function satisfies condition (1.2) for every and , where and the sequence is equiregulated. If the sequence converges pointwisely to a function , then it also converges uniformly to .

      1.1.4 Relatively Compact Sets

      In this subsection, we investigate an extension of the Arzelà–Ascoli

Скачать книгу