[New-Poetry] Re: Books a poet should own

[Roger Day]

In the case I outlined below, a and b are independant variables, so a
cannot be b. The independant variables can have equivalence of value,
but fundamentally, they operate independantly, they are *not the same,
they are two different things (in a computer program, they are two
different slots in the memory, so there is a physical difference).
However, and to contradict myself, the variables a and b can refer to
the same object (languages that operate on references usually contain
this property - Java, Python, PERL). However, a and b are two
different address slots which point to the same object, so attribute
operations on a will effect b: the statement "a is b" might hold water
in this case.

Further, take for example if a and b represented two objects - one a
green horse, the other blue. Languages rarely provide operators for
comparing ad hoc objects, particularly complex objects with "has a"
and "is a" relationships. However, Strings (in some languages or
libraries) now have a whole zoo of likeness operators in
pattern-matches (regular expressions in the jargon). For example,

$h =~ /^a[g-H] \d\d \w .*ll$/;

This is a test which tries to see if the pattern on the RHS (a string
beginning with a, second character g through h, a single space, two
integers, a space, a word, a space, some characters, ending with 2
l's.

So == is (usually) limited in datatypes to (typically) integers,
floats and strings, where identity can be considered a speicial case
for "like". In some languages, == can be overridden so that == can
perform identity on object a and b, but overriding operators is
usually considered to be bad practice. It is very confusing to C or
Basic programmers where such things as overloading can't be done.

Umm. Caveat emptor. This is maths seen from the POV of the programmer.

HTH

Roger
[1] PERL has something *like* the "similarity" operator =~

$x =~ s/A/a/g;

where the string x is operated on by the RH function. This is a
"convenience" operator and I've not seen it in other languages.

On 10/22/06, James Cervantes <cervantes.james at gmail.com> wrote:
> a-ness can be *like* b-ness but a can never be "equal to/with" b???
>
> - Jim
>
> On 10/22/06, Roger Day <rog3r.day at gmail.com> wrote:
> > In computerese
> >
> > for integers, eq or == or .eq. or even equals
> >
> > are identity functions in various languages.
> >
> > if a == b:
> >     <do something interesting>
> >
> > So when a is *identitical* to b in all respects, then something
> > interesting will happen. This isn't similarity: this is a
> > "straightforward" 1 == 1 (where a has a value of  1 and b has a value
> > of 1). This gets interesting if the symbols represent objects.  Can
> > you say 'a' is 'b' in maths? I suppose you could say that == is "is
> > like", but that seem's wrong as well. a is identical is to b seems
> > stronger and more apt. You may think that this is quibbling - and I
> > wouldn't argue with you - but you can't argue with the compiler! And
> > it has it's purposes in a maths and physics, where such fine points
> > are argued endlessly.
> >
> > The notation = can be seen as a mapping function and really should be
> > denoted as <= or <- if this didn't exhaust the notation so
> >
> > x = x + 1
> >
> > the resultant value of the function "x+1" replaces the previous value
> > that x had. So "=" does not equal "similarity" or identity. So the =
> > notation is probably the equivalent of 'has': in the previous previous
> > paragraph, the statements "a has the value of 1" and "b has the value
> > of 1" is denoted by
> >
> > a = 1
> > b = 1
> >
> > Similarity has a lot of play in geometry -  "polygons are similar  if
> > their corresponding (matching) angles are equal and the ratio of their
> > corresponding sides are in proportion." So "like" has a very precise
> > meaning. So for similarity, we have the notation of:
> >
> > =~ (or tilda over the equals).
> >
> > HTH
> >
> > Roger
> >
> > On 10/22/06, Jason Quackenbush <jfq at myuw.net> wrote:
> > > Kazmandu at aol.com wrote:
> > > > When I took physics one of the
> > > > first things the professor said was that '=' means 'is like' not 'is'
> > > > even though we say 'is'.
> > >
> > > That sounds weird to me. As Wittgenstein pointed out in his review of Coffey's "The Science of Logic," a lot of people have a pretty entrenched
> > > confusion between the "is" that's the linguistic copula and the "is" that's an expression of Identity, and I've worked very hard to get the difference
> > > clear in my head. When I see "=" that means identity, or "is" not "is like", to me. What I take it he was saying was that in physics it should be
> > > taken to be more like the copula? I mean, it would really throw all the metaphysicians and mathematical logicians for a loop if "=" really just
> > > expressed a relation that entailed similarity, and maybe that's good enough reason to say that it does, but the more i think about this sentence
> > > above, the more confused I get. Would you mind expounding a bit on what your professor meant by that? I only got a B- in freshman physics.
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> >
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