Page 48 - 36-1
P. 48

Ambiguity Increases and Insurance Deductibles





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             which contradicts Equation (E3). s Equation (E3).
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                  Next,  we  prove  that  Condition  (E4)  holds  for  all            , 1] and           0,      ] through  the , 1] and           0,      ] through  the
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                                Next,  we  prove  that  Condition  (E4)  holds  for  all           
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             following procedure. Let ng procedure. Let
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             Given  that      =          0,      ],            ,     ) is  a  quadratic  function  of           0, 1].  Then,  by  letting      0,      ],            ,     ) is  a  quadratic  function  of           0, 1].  Then,  by  letting
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                    =0, we can find an             ) at which            ,            )) is a local maximum or minimum. ximum or minimum.
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                  Considering the interval in which             ) lies and            ,            )) is a local maximum or        ) lies and            ,            )) is a local maximum or
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                                Considering the interval in which     
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             minimum, we obtain the determining conditions under which      ≤      for all      >0,      <0, ≤      for all      >0,      <0,
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                           minimum, we obtain the determining conditions under which     
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             and            , 1], as follows.     , 1], as follows.
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             Case 1.       Case 1.   ∗    ≤0 �   a t  ∗    �
                            ≤0 at             )     0, ].              )     0, ].
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             Since            ,            )) is a local maximum when             ) lies in   0, ], the condition            ,     ) ≤ 0 ,            )) is a local maximum when             ) lies in   0, ], the condition            ,     ) ≤ 0
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                           Since           
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             for all            , 1] is equivalent to requiring            , +     ) ≤ 0 for 0<      ≤ . , 1] is equivalent to requiring            , +     ) ≤ 0 for 0<      ≤ .
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             Since            ,            )) is a local minimum when             ) lies in   0, ], the condition            ,     ) ≤ 0 ,            )) is a local minimum when             ) lies in   0, ], the condition            ,     ) ≤ 0
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                           Since           
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             for all            , 1] is equivalent to requiring            , 1)≤0. , 1] is equivalent to requiring            , 1)≤0.
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                            ≤0 at             )      , 1].             )      , 1].
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             Since            ,            )) is a local maximum when             )       , 1], the condition            ,     ) ≤ 0 for ,            )) is a local maximum when             )       , 1], the condition            ,     ) ≤ 0 for
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                           Since           
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             all            , 1] is equivalent to requiring            ,            )) ≤ 0. , 1] is equivalent to requiring            ,            )) ≤ 0.
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             Case 4.  � �  � � ,�) Case 4.  � �  � � ,�)  ≥0   a t    ∗  �
                            ≥0 at             )      , 1).             )      , 1).
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             Since            ,            )) is a local minimum when             ) lies in    , 1), the condition            ,     ) ≤ 0 ,            )) is a local minimum when             ) lies in    , 1), the condition            ,     ) ≤ 0
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                           Since           
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             for all            , 1] is equivalent to requiring            , +     ) ≤ 0 and            , 1)≤0, where 0<     ≤ . , 1] is equivalent to requiring            , +     ) ≤ 0 and            , 1)≤0, where 0<     ≤ .
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                            ≥0 at             )=1. ≥0 at             )=1.
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             Case 5.       Case 5.   ∗           ∗
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