<div style="font-family: 'Times New Roman'; font-size: 16px;"><br /><br /><span>On 23/08/12, <b class="name">Brent Yorgey </b> <byorgey@seas.upenn.edu> wrote:</span><blockquote cite="mid:20120823150217.GA20076@seas.upenn.edu" class="iwcQuote" style="border-left: 1px solid #00F; padding-left: 13px; margin-left: 0;" type="cite"><div class="mimepart text plain"><br /><br />fun1 returns 8 for all inputs. The fact that fun1's definition uses<br />the name 'constant' which happens to have the same name as something<br />in scope is irrelevant. For example, this is precisely the same as the above:<br /><br />constant :: Int<br />constant = 1<br />fun1 :: Int -> Int<br />fun1 foo = 8<br /><br />-Brent</div></blockquote>Yes, I am aware the semantics of Haskell is this situation. <br _moz_dirty="" />
I also know for every model of a subclass there must exist a model of the super-class.<br _moz_dirty="" />
I am just not sure whether there is a model expansion from the super-class model to the subclass model.<br _moz_dirty="" />I am also unsure of the morphism from type variables in the class definition to actual types in instances and to the operations in the instance.<br _moz_dirty="" />In a intuitive way I think that I understand these things, but not in a model theoretic way.<br _moz_dirty="" />
<br _moz_dirty="" />
Thanks,<br _moz_dirty="" />
Pat<br _moz_dirty="" /><br _moz_dirty="" /><br _moz_dirty="" /></div>
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