30 March 2006

'Do not leave your baggage unattended'

'Do not leave your baggage unattended.'
(A common sign on Sydney buses.)

Observation
Not sure how to parse this sentence; options are:

(a) Split Verb
The verb 'to leave something unattended' has been split by 'your baggage'.
ie. [Do not leave] + [your baggage] + [unattended]

(b) Reverse Noun Modifier
The modifier 'unattended' is placed after the modified 'your baggage'.
ie. [Do not leave] + [your baggage < unattended]

Both are possible, but which one is preferred for ease of parsing?

2006-03-30 10:33:00am (GMT +10 -1) kyy

'You're sooo funny.'

'You're sooo funny.'

Observation
If a word cannot be found in a dictionary lookup, check to see if there is a string of 3 or more repeated letters. If so, then remove a repeated letter one at a time and look up the dictionary to see if the remaining letters form a word.

NB: The condition must be a string of 3 or more repeats because some words have double repeats, e.g. vacuum.

Other examples
1. 'Whateverrr!'
2. 'Shiiiiiit!'
3. 'Zzzzzzzzz....' (There should be a word in the dictionary 'zzz' meaning *Indication that author is sleepy.)

2006-03-30 10:16:00am (GMT +10 -1) kyy

'It's oh-so elegant.'

'It's oh-so elegant.'

(Ad copy for Westfield)

Observations
1. If a hyphenated word cannot be found in a dictionary lookup, parse its constituent words separately. eg. Parse 'oh-so' as 'oh' (modifier) + 'so' (modified)
2. 'oh' is being used here as a modifier of 'so', meaning 'very', ie. the sentence above translates as 'It's so very elegant' or 'It's soooo elegant'.

2006-03-30 10:03:00am (GMT +10 -1) kyy

22 March 2006

Generality from the Singular or the Plural

A general concept may be indicated by the singular or plural form in English.

e.g. 'Gift Certificate Available' or 'Gift Certificates Available'


Stimulus: Sign in shop window, Petersham.

2006-03-22 12:04:00pm (GMT +10 -1) kyy

Solution to Zeno's Second Paradox

Zeno’s Second Paradox purports to show that in a chase, the chaser can never catch the person or object being chased. In the paradox the Greek hero Achilles graciously gives his slower rival, which legend has turned into ‘The Tortoise’, a head start.

At the start of the race, Achilles is at position 0 while the tortoise is at the 1 kilometre mark. For convenience, imagine that the tortoise can only run half as fast as Achilles.

Common sense may lead you to think that Achilles would overtake the tortoise after running 2 kilometres. However, by the time Achilles reaches the tortoise’s starting point at the 1 km mark, the tortoise has travelled ½ km ahead, which is 1 + ½ km from Achilles’ starting point at position 0. When Achilles reaches the 1½ km point, the tortoise has reached 1 + ½ + ¼ km, and so on.

When, after N steps, Achilles reaches a distance 2 – (½ )N-1 from the start the tortoise is still in the lead because it is at a distance 2 – (½ )N+1 from the start. No matter how big N (the number of divisions of the journey) becomes, Achilles never overtakes the tortoise!

The Solution

The solution I propose involves the observation that the pursuer and the pursued are finite entities. (As such is substantially similar to my resolution of Zeno’s First Paradox.)

Say Achilles has a stride length of 2 metres, and the tortoise has a stride length of 1 metre – this tortoise likes to bound along rather than waddle. For convenience, let’s give the tortoise a 10 metre head start. All else being the same (i.e. Achilles and the tortoise takes the same time to make each stride), after 5 strides Achilles is at the 1 km mark, and the tortoise is at the 1.5 km mark. After another 5 strides Achilles will catch up to the tortoise at the 2 km mark.

The crucial thing here is that both Achilles and the tortoise have a finite stride length that remains constant throughout the race. In Zeno’s footrace on the other hand, Achilles and the tortoise make smaller and smaller strides, so that near the 2 km mark they are making infinitessimally small strides. In fact, Achilles never catches up to the tortoise in the Zeno’s Paradox because neither of them ever reaches the 2 km mark. (If you imagine Achilles running the race by himself, you get a situation that is identical to Zeno’s First Paradox.)

The upshot of comparing these two descriptions of the race is that for Zeno’s Second Paradox to be true, both the pursuer and the pursued must be able to reduce their ‘stride length’ an infinite number of times. The only thing that fits this condition is a point (or a line that runs perpendicular to the direction of the race track).

Finite objects such as people and tortoises can reduce their stride length, but not any smaller than the size of their bodies. So the number of reductions they can achieve is finite.

Assuming that there can be no object of a size between a point and an object with finite size, what this means is that when a finite object moves, it does so in finite increments, and there is a minimum finite amount of movement for each finite object.

Further questions

One question which springs to mind is whether there is a smallest finite amount of movement.

Another is whether there is such a thing as a smallest finite anything. While it’s true that a point, being infinitessimal, is smaller than all finite objects, this does not answer the question of whether there is a smallest among finite objects.


Stimulus: "The Infinite Book", by John D. Barrow. The description of Zero's Second Paradox is largely drawn from pages 21-22 of Barrow's book and also from Zeno's Paradoxes at Wikipedia.com.

2006-03-22 11:48:00am (GMT +10 -1) kyy

21 March 2006

The Third Article (Beyond the Definite and Indefinite)

Examples of sentences where neither the definite article 'the' nor the indefinite article 'a' is best

1. "What's the best software to use for watching dvd on computer?"

Compare: "what's the best software to use for watching dvd on (the) computer?
or "what's the best software to use for watching dvd on (a) computer?"

2. "Save it to disk."

2006-03-21 04:57:00pm (GMT+10 -1) kyy

Writing affects language

'blog' from 'web log' ...

... is another example of how written script affects the (spoken) language. This kind of word creation is not possible with languages written in non-alphabetic script, e.g. Chinese.

The archetypal example is the use of acronyms to abbreviate phrases and create new words in languages with alphabetic scripts, e.g. 'scuba' from 'self-contained underwater breathing apparatus'.

2006-03-20 05:52:31pm (GMT+10 -1) kyy

20 March 2006

Solution to Zeno's Paradox

*Zeno's Paradox (actually the first of four) purports to show that motion is impossible.

If you want to walk from one point to another, you must first cross half the distance, then to cross the remaining distance, you must first cross half of the remainder, and so on.

If the distance you want to walk is 1 kilometre long, you will first reach 1/2 km from your start, then 3/4 km from your start (1/2 + 1/4), then 3/4 km (1/2 + 1/4 + 1/8), then 7/8 and so on. After you have taken N steps of the journey, you will have gone a distance equal to 1-(1/2)N kilometres. No matter how big N becomes (that is, no matter how many successive half-distances you cover), this distance will always be less than 1 and you will never arrive at your destination.

(Another permutation of Zeno's First Paradox seemingly prevents you from leaving your starting point. Before you can cross a given distance you must first cross half the distance, but before you can do that you must cross half that half-distance, ad infinitum.)

The solution I propose involves observing that Zeno's First Paradox assumes the person or object doing the moving is infinitely small, eg. a point (or a line perpendicular to the direction of travel).

Say your walking stride length is 1 metre, and for convenience the distance to your destination is 10 metres.

Using these figures, it's easy to see that it will take you 10 strides to reach your destination. Working through the paradox, to reach 10 m you must first reach 5 m, which you easily can cover in 5 strides. From this point to reach half the remainder (7.5 m from the start), you only need 3 more strides. In fact, with 3 more strides you exceed that distance. To fit with the paradox, you must reduce your stride length and keep on doing it so that you don't exceed each subsequent half-distance. And you must do so an infinite number of times in order to never reach your destination.

However, this is only possible with an object of zero size. If we started with an object with finite (positive) size, like a tortoise or a human, and measured the stride lengths from one heel to the next, at some point in our stride-length-reducing exercise the heel of a foot would exceed the length that is left to travel, so that the tortoise or human can be said to have arrived at the destination.

Interestingly, by merely changing how we measure stride-lengths in this scenario, we can illustrate the non-arrival of a zero-sized object. By measuring toe to toe rather than heel to heel, we in effect have a zero-sized object which, with ever reducing stride lengths, never arrives at its intended destination.

A funny way of describing this is that in order to 'prove' that motion is impossible using Zeno's Paradox, you must purposefully try not to reach your destination (that is, by successively reducing your stride length).

(You can perform this thought experiment using a line segment of finite size. Imagine you have a 1 metre long ruler. For the first 5 m, you 'walk' or flip the ruler end to end to cover the distance.

Then for the next 2.5 m you can flip the ruler for two-lengths, then angle the ruler so that it covers the remaining 1/2 metre without exceeding it. And so on. Over time, the final angle of the rulers gets more and more oblique as the final 'stride' distance gets progressively smaller.)

Therefore an object with a finite size can traverse a finite distance, but an object that is infinitely small cannot do the same.

This solution has a couple of interesting ramifications. The first is that since a point is infinitely small, its 'stride length' is infinitely reducible and it can satisfy Zeno's First Paradox, namely a point cannot move. Points can mark positions but they cannot traverse a finite distance.

Conversely, a moving object cannot be a point. If you observe an object travelling from one point to another, the object must have a finite size, no matter how small. Motion is a property of finiteness.

Stimulus: "The Infinite Book", by John D. Barrow. The description of Zeno's paradox above is largely drawn from pages 20-21.

kyy 2007-04-02 1542 z+10

*Note: This is version 1.1 of the solution. The first two comments below refer to version 1.0 of the solution, which published by kyy on 2006-03-21 1332 z+9.