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Topic: Surprise at my failure to resolve an issue in an elementary paper by Rado
Replies: 44   Last Post: Nov 10, 2013 12:23 PM

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 Peter Percival Posts: 2,623 Registered: 10/25/10
Re: Surprise at my failure to resolve an issue in an elementary paper

Posted: Nov 4, 2013 7:38 AM

Paul wrote:
> About three days ago, I got stuck when reading a paper by the great combinatorist, Rado.

I hope you get the reply you're hoping for.

Meanwhile your title "Surprise at my failure to resolve an issue in an
elementary paper by Rado" reminded me of my students days: I was
surprised if I understood a journal paper. I failed to understand stuff
in many a textbook. For example, I couldn't get past page 21 (I think
it was) in Sacks's 'Saturated model theory'.

This paragraph may not mean anything to you, in which case skip to the
next one. Sacks was defining S |= phi (S a structure, phi a formula).
I knew of two definitions: Taski's and McKinsey's. I could see (without
the need to understand) that Sack's method wasn't Tarski's. So I
assumed that it was McKinsey's or a near relative. I worked backwards
knowing that "S |= phi" meant "phi is true in S", and was able to
understand what a map (called sigma by Sacks, I seem to recall) was
doing. Sacks's explanation was utterly obscure (to me--I was, and I
remain, thick) but by keeping McKinsey's definition in mind I came to
understand what sigma was.

I think my experience described in the previous paragraph may be broadly
relevant. If you know, from some other source, what Rado's Theorem 1
means (and maybe how to prove it, but, chiefly, what it means), can you
work backwards from the conclusion that you know and understand and thus

--
Du mußt Amboß oder Hammer sein
Goethe

Date Subject Author
11/3/13 Paul
11/3/13 David Hartley
11/3/13 fom
11/3/13 fom
11/3/13 fom
11/4/13 fom
11/4/13 Paul
11/4/13 Paul
11/4/13 Peter Percival
11/4/13 David Hartley
11/4/13 Paul
11/4/13 David Hartley
11/4/13 Paul
11/4/13 David Hartley
11/4/13 Paul
11/5/13 Paul
11/5/13 David Hartley
11/5/13 Paul
11/5/13 David Hartley
11/5/13 Paul
11/6/13 Paul
11/6/13 Paul
11/7/13 Paul
11/7/13 David Hartley
11/7/13 Paul
11/7/13 David Hartley
11/7/13 Paul
11/7/13 David Hartley
11/7/13 David Hartley
11/7/13 Paul
11/7/13 David Hartley
11/8/13 Paul
11/8/13 David Hartley
11/7/13 Paul
11/7/13 fom
11/8/13 Paul
11/8/13 David Hartley
11/10/13 Paul
11/10/13 David Hartley
11/10/13 Paul
11/10/13 David Hartley
11/10/13 David Hartley
11/10/13 Paul
11/4/13 Paul
11/4/13 Peter Percival