Darren New wrote:
> Invisible wrote:
>> proof by reduction to the wrong problem:
> 
> I liked one that we got in a class on parallel processing. Prof writes 
> up an algorithm that doesn't have any loops (since it's done in 
> parallel). He says "This is order one.  Proof by ... well, proof by 
> inspection.  Look at it!"
> 

Reminds me that one of my maths teachers, at high school, once wrote an 
equation on the blackboard and said “It is obvious that…”  Looked at the 
board again, left the room, came back 15 minutes later and said “Yes, it 
is obvious that...”

-- 

Best Regards,
	Stephen

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Stephen <mca### [at] aoldotcom> wrote:
> Reminds me that one of my maths teachers, at high school, once wrote an 
> equation on the blackboard and said ???It is obvious that??????  Looked at the 
> board again, left the room, came back 15 minutes later and said ???Yes, it 
> is obvious that...???

  Many teachers of technical subjects have their odd and funny quirks. The
higher the school level, the more likely. This is especially true at
university level, probably because a professorship is a more or less permanent
tenure (at least in many countries) and they don't have to worry too much
about getting fired (this is done intentionally because it's seen as
promoting free and radical thinking without the fear of losing their jobs).

  (Of course this can have negative side-effects as well. You hear all the
time stories about university professors spending an antire lecture ranting
about politics, especially in the US, even though the course subject has
absolutely nothing to do about that (eg. it's a math or physics course).)

-- 
                                                          - Warp

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On 02/06/10 03:42, Warp wrote:
>   (Of course this can have negative side-effects as well. You hear all the
> time stories about university professors spending an antire lecture ranting
> about politics, especially in the US, even though the course subject has
> absolutely nothing to do about that (eg. it's a math or physics course).)

	I'm sure this is very rare. Never heard this happening in any of the
two universities I was in over a period of 11 years.

-- 
A closed mouth gathers no feet...

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On 6-2-2010 12:42, Warp wrote:
> Stephen <mca### [at] aoldotcom> wrote:
>> Reminds me that one of my maths teachers, at high school, once wrote an 
>> equation on the blackboard and said ???It is obvious that??????  Looked at the 
>> board again, left the room, came back 15 minutes later and said ???Yes, it 
>> is obvious that...???
> 
>   Many teachers of technical subjects have their odd and funny quirks. The
> higher the school level, the more likely. This is especially true at
> university level, probably because a professorship is a more or less permanent
> tenure (at least in many countries) and they don't have to worry too much
> about getting fired (this is done intentionally because it's seen as
> promoting free and radical thinking without the fear of losing their jobs).

I can only speak for myself. I was teaching digital technology at an 
applied university to electrical engineering students for the last half 
year. I deliberately tried to make sure they were thinking I am slightly 
strange. (Which is quite close to reality off course). In almost every 
test there were strange questions and strange answers.
The purpose of this is to force them to think every time whether I mean 
it or not. E.g my first test contained the question 'do you think I am 
weird?' (embedded in a boolean disjunction). I explained later to them 
that if they think so and answer truthfully, that answer is obviously 
correct. Hopefully next time they don't assume it is a trick question if 
I ask something simple.
One other thing I am rather proud of is asking before a test who was 
left and who was right handed and handed out papers accordingly. Can 
anyone guess what the difference was?
I also think that for this group being weird *and* knowledgeable gives 
them more trust that I really know what I am talking about and not just 
have read a week in advance in the reader.

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andrel wrote:
> Can anyone guess what the difference was?

Direction of axes?

-- 
Darren New, San Diego CA, USA (PST)
   Forget "focus follows mouse." When do
   I get "focus follows gaze"?

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On 6-2-2010 22:01, Darren New wrote:
> andrel wrote:
>> Can anyone guess what the difference was?
> 
> Direction of axes?
> 
That would work in a physics test, but an interesting suggestion. This 
was just about and/or/not/xor and representation of integers.

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andrel wrote:
> One other thing I am rather proud of is asking before a test who was 
> left and who was right handed and handed out papers accordingly. Can 
> anyone guess what the difference was?

The side of the page that the name went on?

...Chambers

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On 7-2-2010 20:22, Chambers wrote:
> andrel wrote:
>> One other thing I am rather proud of is asking before a test who was 
>> left and who was right handed and handed out papers accordingly. Can 
>> anyone guess what the difference was?
> 
> The side of the page that the name went on?

close but no cigar

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On 6-2-2010 21:45, andrel wrote:

> One other thing I am rather proud of is asking before a test who was 
> left and who was right handed and handed out papers accordingly. Can 
> anyone guess what the difference was?

It seems that we don't have other suggestions. Possibly too deep into a 
discussion that nobody wants to read anymore. ;)

The simple answer is that the students had to fill in a truthtable 
referring to a figure that was printed next to it. If that figure is on 
the left of the table left handed people would hold there hand in front 
of it while filling it in, and mutatis mutandis* for right handed 
people. So I made two versions where the order of the figure and table 
was switched. Actually it is so logical to do so that it surprised me a 
little that nobody seems to do this. The students never had seen it, not 
my colleagues nor the group that coordinated all the tests for the 
university.


*) Latin for 'change what has to be changed' a common expression in the 
Netherlands but possibly not all over the globe**

**) once a rewiewer of a paper flamed us for using this expression. We 
hadn't realised that this expression might not be common elsewhere. So 
he had a point. He said that we should not use latin and used 
expressions like 'deliberate obfuscate' and at least either 'e.g.' or 
'i.e.' so that was quite funny.

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Invisible wrote:
> http://www.princeton.edu/~sacm/humor/proof.html

Related:
http://i163.photobucket.com/albums/t309/philipquarles/methods.gif

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