Showing Revision 1 created 10/03/2012 by Amara Bot.

1. Title:
   21-07 Functional Properties Solution
2. Description:

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   The first one of course is not a functional property because condition two is not fulfilled.
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   All computer programs are computer programs.
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   There is no computer program that is not a computer program.
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   Of course, this sounds a bit silly but it's actually
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   the only example I could think of where this condition here is violated.
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   A program always returns one already is a functional property.
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   First of all, it describes how output relates to the input
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    namely output doesn't care about the input and is always one
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    and property two is also always satisfied.
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    For example, there are computer programs that I could write that always return two
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    and property two is fulfilled for all the other three as well, so I won't even mention it anymore.
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    A program solves vertex cover?
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    Yes, definitely that describes an input-output behavior, how output relates to the input.
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    Is a computer a virus? I would say yes, this is a functional property.
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    Now, it is a bit debatable if saying it is a computer virus
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    already described sufficiently how the output relates to the input
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    but I would say that probably any definition of a computer virus that you would give me
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    would in some way describe what the computer virus is doing.
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    So, it might ignore anything that receives and overwrite your hard disc,
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    so put something in the memory, or it might lock your screen.
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    So, I would say here, the input-output behavior is variable
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    depending on how you define computer virus but it is always defined.
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    Now, the final one that is a bit of a tricky one saying that
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    a program only requires linear time is not a functional property
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    because that does not describe how the output relates to the input.
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    It is the property of the program but it is not a functional property
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    because it doesn't ask what does the program do
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    and what does the program do is actually this relationship here.
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    It only asked how fast that the program are doing that.
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    This is something that is a little more tricky to figure out,
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    but basically, any time that you ask can a program do X
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    that will be a functional property that you are asking for
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    at least in almost any of the cases.