Re: SQL Trees
From: Mikito Harakiri <mikharakiri_at_iahu.com>
Date: Mon, 7 Jun 2004 11:27:59 -0700
Message-ID: <YD2xc.34$7o2.220_at_news.oracle.com>
> "Vadim Tropashko" <vadimtro_at_yho.cm> wrote in message
> news:ppnwc.4$_a1.87_at_news.oracle.com...
> > ... Materialized path encoding and Farey/Continued Fractions/Moebius
> > transformations/Orthogonal 2x2 matrices. ...
> -----------------^^^^^^^^^^^
>
> They are not orthogonal. The inverse of Matrix(2,2,[[5,1],[1,0]]), for
> example, is Matrix(2,2,[[0,1],[1,-5]]) which is not transpose.
Date: Mon, 7 Jun 2004 11:27:59 -0700
Message-ID: <YD2xc.34$7o2.220_at_news.oracle.com>
"Mikito Harakiri" <mikharakiri_at_iahu.com> wrote in message
news:z51xc.25$7o2.178_at_news.oracle.com...
> "Vadim Tropashko" <vadimtro_at_yho.cm> wrote in message
> news:ppnwc.4$_a1.87_at_news.oracle.com...
> > ... Materialized path encoding and Farey/Continued Fractions/Moebius
> > transformations/Orthogonal 2x2 matrices. ...
> -----------------^^^^^^^^^^^
>
> They are not orthogonal. The inverse of Matrix(2,2,[[5,1],[1,0]]), for
> example, is Matrix(2,2,[[0,1],[1,-5]]) which is not transpose.
Speaking of transpose, here is a cute property:
Let mirror path be the path in the reverse order. For example, the reverse of
They have reverse matrix representations! In the above case transposed matrix
Naturally, palindrome paths correspond to symmetric matrices. Received on Mon Jun 07 2004 - 20:27:59 CEST