Clarification on prove regarding Continuous, increasing functions and $limsup$
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For every continuous increasing function $u:mathbb R_+tomathbb R_+$ and every nonnegative sequence $(x_n)$, $$limsuplimits_nu(x_n)=uleft(limsuplimits_nx_nright).$$
let $x_n_i rightarrow limsuplimits_nx_n$
Hence $limsuplimits_nu(x_n)geqlim u(x_n_i)=u(limsuplimits_nx_n) $, since $u$ is continuous.
Let $u(x_n_j)rightarrow limsuplimits_nu(x_n) $
$forall epsilon>0$ $exists J$ $forall jgeq J$ $ x_n_j< limsuplimits_nx_n + epsilon $
Since $u$ is increasing,
$u(x_n_j)leq u(limsuplimits_nx_n + epsilon)$
Hence, $limsuplimits_nu(x_n)= lim u(x_n_j)leq u(limsuplimits_nx_n + epsilon) $ for all $epsilon$
Since $u$ is continuous let $epsilon rightarrow 0$
Hence $limsuplimits_nu(x_n)leq u(limsuplimits_nx_n) $
calculus continuity limsup-and-liminf
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For every continuous increasing function $u:mathbb R_+tomathbb R_+$ and every nonnegative sequence $(x_n)$, $$limsuplimits_nu(x_n)=uleft(limsuplimits_nx_nright).$$
let $x_n_i rightarrow limsuplimits_nx_n$
Hence $limsuplimits_nu(x_n)geqlim u(x_n_i)=u(limsuplimits_nx_n) $, since $u$ is continuous.
Let $u(x_n_j)rightarrow limsuplimits_nu(x_n) $
$forall epsilon>0$ $exists J$ $forall jgeq J$ $ x_n_j< limsuplimits_nx_n + epsilon $
Since $u$ is increasing,
$u(x_n_j)leq u(limsuplimits_nx_n + epsilon)$
Hence, $limsuplimits_nu(x_n)= lim u(x_n_j)leq u(limsuplimits_nx_n + epsilon) $ for all $epsilon$
Since $u$ is continuous let $epsilon rightarrow 0$
Hence $limsuplimits_nu(x_n)leq u(limsuplimits_nx_n) $
calculus continuity limsup-and-liminf
add a comment |Â
up vote
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up vote
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For every continuous increasing function $u:mathbb R_+tomathbb R_+$ and every nonnegative sequence $(x_n)$, $$limsuplimits_nu(x_n)=uleft(limsuplimits_nx_nright).$$
let $x_n_i rightarrow limsuplimits_nx_n$
Hence $limsuplimits_nu(x_n)geqlim u(x_n_i)=u(limsuplimits_nx_n) $, since $u$ is continuous.
Let $u(x_n_j)rightarrow limsuplimits_nu(x_n) $
$forall epsilon>0$ $exists J$ $forall jgeq J$ $ x_n_j< limsuplimits_nx_n + epsilon $
Since $u$ is increasing,
$u(x_n_j)leq u(limsuplimits_nx_n + epsilon)$
Hence, $limsuplimits_nu(x_n)= lim u(x_n_j)leq u(limsuplimits_nx_n + epsilon) $ for all $epsilon$
Since $u$ is continuous let $epsilon rightarrow 0$
Hence $limsuplimits_nu(x_n)leq u(limsuplimits_nx_n) $
calculus continuity limsup-and-liminf
For every continuous increasing function $u:mathbb R_+tomathbb R_+$ and every nonnegative sequence $(x_n)$, $$limsuplimits_nu(x_n)=uleft(limsuplimits_nx_nright).$$
let $x_n_i rightarrow limsuplimits_nx_n$
Hence $limsuplimits_nu(x_n)geqlim u(x_n_i)=u(limsuplimits_nx_n) $, since $u$ is continuous.
Let $u(x_n_j)rightarrow limsuplimits_nu(x_n) $
$forall epsilon>0$ $exists J$ $forall jgeq J$ $ x_n_j< limsuplimits_nx_n + epsilon $
Since $u$ is increasing,
$u(x_n_j)leq u(limsuplimits_nx_n + epsilon)$
Hence, $limsuplimits_nu(x_n)= lim u(x_n_j)leq u(limsuplimits_nx_n + epsilon) $ for all $epsilon$
Since $u$ is continuous let $epsilon rightarrow 0$
Hence $limsuplimits_nu(x_n)leq u(limsuplimits_nx_n) $
calculus continuity limsup-and-liminf
edited Aug 16 at 9:49
asked Aug 16 at 9:43
Jhon Doe
397211
397211
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