From: David R Tribble on
WM wrote:
>> Mathematics is physics (V. A. Arnold).
>

David R Tribble wrote:
>> What is the physical focal length of a diopter 0 lens?
>

WM wrote:
> What a pity that Arnold died. Now we will never get the answer.
> Nevertheless, your question is physics with no doubt.

Yes, it is a question about physics.
So what is the physical focal length of a diopter 0 lens?
From: David R Tribble on
WM wrote:
>> My proof does not show which line is left. But it shows that finished
>> infinity is a non-mathematical notion. Of course it is always the last
>> line that is left, and it is impossible to get rid of a last line,
>> though the contents of the last line may change as often as desired.
>

David R Tribble wrote:
>> Non sequitur. If the contents of the last line changes, then
>> obviously that must be a different last line. There must therefore
>> be more than one line you call the "last line".
>

WM wrote:
> The last line only temporarily deserves that name.

Then there is no last line at all.
From: Simplane Simple Plane Simulate Plain Simple on
On Jun 11, 8:14 am, WM <mueck...(a)rz.fh-augsburg.de> wrote:
> On 11 Jun., 16:47, David R Tribble <da...(a)tribble.com> wrote:
>
> > WM wrote:
> > > Mathematics is physics (V. A. Arnold).
>
> > What is the physical focal length of a diopter 0 lens?
>
> What a pity that Arnold died. Now we will never get the answer.
> Nevertheless, your question is physics with no doubt.
>
> Regards, WM

Colenbrander, Fletcher – Low Vision Rehabilitation – JCAHPO, Anaheim –
November 2003
14
APPENDIX II – NOMOGRAM for VISUAL ACUITY CALCULATIONS
LETTER SIZE VIEWING DISTANCE VISUAL ACUITY ICD
40 M -30 80 m 145 250 ft 1/0.5 2.0 115 20/10
60 m 140 200 ft
30 M -25 J#24 0.02 D 50 m 135 160 ft 1/0.6 1.6 110 20/12
40 m 130 120 ft
25 M -20 J#23 30 m 125 100 ft 1/0.8 1.2 105 20/16
25 m 120 80 ft
20 M -15 J#22 0.05 D 20 m 115 60 ft 1/1 1.0 100 20/20
16 m 110 50 ft
16 M -10 J#21 12 m 105 40 ft 1/1.2 0.8 95 20/25
Range of Normal Vision
0.10 D 10 m 100 30 ft
12 M -5 100 p J#20 8 m 95 25 ft 1/1.6 0.6 90 20/30
6 m 90 20 ft
10 M 0 80 p --- 5 m 85 16 ft 1/2 0.5 85 20/40
0.25 D 4 m 80 12 ft
8 M 5 60 p J#19 3 m 75 10 ft 1/2.5 0.4 80 20/50
2.5 m 70 8 ft
6 M 10 50 p J#18 0.5 D 2 m 65 6 ft 1/3 0.3 75 20/60
Near-normal Vision
1.6 m 60 5 ft
5 M 15 40 p --- 1.2 m 55 50” 1/4 0.25 70 20/80
1 D 1 m 50 40”
4 M 20 32 p J#17 80 cm 45 30” 1/5 0.2 65 20/100
(16) 60 cm 40 25”
3 M 25 24 p J#15 2 D 50 cm 35 20” 1/6 0.16 60 20/120
2.5 D 40 cm 30 16”
2.5 M 30 20 p J#14 3 D 30 cm 25 12” 1/8 0.12 55 20/160
Moderate Low Vision
4 D 25 cm 20 10”
2 M 35 16 p J#13 5 D 20 cm 15 8” 1/10 0.1 50 20/200
6 D 16 cm 10 6”
1.6 M 40 12 p J#12 8 D 12 cm 5 5” 1/12 0.08 45 20/250
(11) 10 D 10 cm 0 4“
1.2 M 45 10 p J#10 12 D 8 cm -5 3“ 1/16 0.06 40 20/300
(8,9) 15 D 6 cm -10 2.5”
1 M 50 8 p J# 7 20 D 5 cm -15 2” 1/20 0.05 35 20/400
Severe Low Vision
(6) 25 D 4 cm -20 1.6”
0.8 M 55 6 p J# 5 30 D 3 cm -25 1.2” 1/25 0.04 30 20/500
(4) 40 D 2.5 cm -30 1”
0.6 M 60 5 p J# 3 50 D 2 cm -35 0.8” 1/30 0.03 25 20/600
60 D 1.6 cm -40 0.6”
0.5 M 65 4 p J# 2 80 D 1.2 cm -45 0.5” 1/40 0.025 20 20/800
100 D 1 cm -50 0.4”
0.4 M 70 3 p J# 1 125 D 0.8 cm -55 0.3” 1/50 0.02 15 20/1000
Profound Low Vision
Formulas used:
1/M X m = m / M = V (visual acuity) (B)
M X D = M x 1/m = 1/V (magnification need) (C)
Size
credit
+ Distance
credit
= Acuity
score (D)
See text for discussion and explanation.
From: David R Tribble on
WM wrote:
>> How would you get to an infinite number of steps when each step has
>> another finite number?
>

David R Tribble wrote:
>> If each step is followed by another finite number step, how would
>> you stop at any finite step?
>

WM wrote:
> It is not necessary to stop somewhere in order to remain in the finite
> domain.

If you don't stop at any finite step, how can the list be incomplete?
From: Virgil on
In article
<c34d244c-dd51-4470-b6e6-82aa2920efaa(a)x27g2000yqb.googlegroups.com>,
WM <mueckenh(a)rz.fh-augsburg.de> wrote:

> On 11 Jun., 08:03, Virgil <Vir...(a)home.esc> wrote:
>
> > > My proof does not show which line is left.
> >
> > It also does not show that any line is left.
>
> Sorry, but you seem unwilling or unable to understand my proof.

I do not find it to be a proof.
> >
> > > But it shows that finished
> > > infinity is a non-mathematical notion.
> >
> > On the contrary, what can be defined cannot be barred from mathematical
> > consideration, and "finished" infinity can be and has been defined.
>
> To be defined means to be called by a shorter name. To have a name
> does not prove existence of the named. Think of several Gods which
> have ceased to have believers.
> >
> > > Of course it is always the last
> > > line that is left, and it is impossible to get rid of a last line
> >
> > Except that the process requires passing by every line so that there
> > cannot be a last one.

In order to pass any line, there must have already been a successor line
in existence to pass to, so one can pass from one line to another line ,
but never pass from one line to no line.
> >
> > So if WM finds a last line, WM is talking of a different process.
>
> No I am looking at it from another position.
> If all lines are there, all can be considered and removed.

Only by completion of the infinite process.

> That is the one side.
> If no line is removed before the next is written, then not all can be
> removed.

That presumes that the entire infinite process cannot be completed, so
cannot be used to prove that it cannot be completed.
>
> In case of finished infinity both statements must be true.

But not simultaneously.

One of them is true only during the process, and the other only after
the process has stopped, so they need not be simultaneously true, and
thus there is no conflict.