Author Topic: Term Post Eye Tiable i.e. PET  (Read 872 times)

jarnos

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Term Post Eye Tiable i.e. PET
« on: January 12, 2021, 04:17:27 PM »
I would like to discuss about the history of the term post-eye-tiable (PET for short) and about the concept in general and about closely related concepts and definitions in this thread.

I found a couple of descriptions for the term:

1. https://igkt.net/sm/index.php?topic=5254.0 that also discusses about some other terms:
"PET - Post Eye Tiable. This is the concept of tying a rope end to an endless rail (or a toroid) where the knot can be fully formed in a one-step process after the rope has been passed around the rail, or through a ring. That is, a knot-free rope first makes a loop around the endless rail, then the knot is tied."

2. is an answer https://outdoors.stackexchange.com/a/22087/20453 for a related question:
"Post eye tiable means that the rope is passed through the eye or harness before any part of the knot is tied." (other 'any' trimmed by me)

The concept is non-trivial for loop knots i.e. eye knots, I mean fixed loop knots that do not contain a knot that can move along the working part. A noose knot is always tied in PET way so it is trivial.

I think it is not needed to pass the rope end through the eye, if you use a bight.

I wonder what was the original meaning of the 'eye' in the term? Does it refer to the eye, the object, to which the knot is tied to, or to the eye of the knot that is to be constructed by tying a knot? One could think the eye of the knot does not exist before tying the knot :)

Attempt for an alternative definition for post-eye-tiable without mentioning an object that the eye is connected to:
A knot is post-eye-tiable in respect of its eye if and only if there exists a tying method for the knot such that no knot except maybe a tiable-in-a-bight knot is needed before the first threading that forms the eye of the knot and that threading must make the eye smaller, and a bight is not threaded over the eye later on in the tying process.

Example: With that definition the Bowline on a bight (ABoK#1080) is PET in respect of its first eye (provided you have access to the working end), but not in respect of its second eye. The knot is also tiable-in-a-bight, but not by the same tying method than it is partially PET.
« Last Edit: January 13, 2021, 01:21:20 PM by jarnos »
Jarno Suni

agent_smith

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Re: Term Post Eye Tiable i.e. PET
« Reply #1 on: January 14, 2021, 09:12:06 AM »
Hello jarnos:

Go to this link: http://www.paci.com.au/knots.php

Download and read: 'An analysis of the structure of Bowlines' (VER 3.0)... at #4 in the table.

Perhaps most of your questions will be answered in that document...

Groundline

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Re: Term Post Eye Tiable i.e. PET
« Reply #2 on: January 14, 2021, 05:05:27 PM »
Hello jarnos:

Go to this link: http://www.paci.com.au/knots.php

Download and read: 'An analysis of the structure of Bowlines' (VER 3.0)... at #4 in the table.

Perhaps most of your questions will be answered in that document...

The PACI password I have used before no longer works.
Don't look at the Sun.

jarnos

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Re: Term Post Eye Tiable i.e. PET
« Reply #3 on: January 14, 2021, 07:32:13 PM »
The PACI password I have used before no longer works.

The password is given in the document.

Besides, the "Knotting terminology" document (http://www.paci.com.au/downloads_public/knots/Knot_Glossary_Robert-Birch.pdf) has terms explained, too. It does not have a password.
Jarno Suni

jarnos

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Re: Term Post Eye Tiable i.e. PET
« Reply #4 on: January 14, 2021, 08:21:56 PM »
Download and read: 'An analysis of the structure of Bowlines' (VER 3.0)... at #4 in the table.

Hello agent_smith. Thanks for the directions. The document has this definition for PET without mentioning an object the eye is connected to:
Quote
If all knot tying maneuvers can be completed after the eye has been formed ? the knot is ?PET?.

My definition is somewhat different: E.g. a TIB knot may exist before forming the eye. Even if there was no such a knot needed some other maneuvers such as forming a loop (like in case of a bowline) may be needed before forming the eye.
Jarno Suni

Groundline

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Re: Term Post Eye Tiable i.e. PET
« Reply #5 on: January 14, 2021, 10:39:59 PM »
The PACI password I have used before no longer works.

The password is given in the document.

Besides, the "Knotting terminology" document (http://www.paci.com.au/downloads_public/knots/Knot_Glossary_Robert-Birch.pdf) has terms explained, too. It does not have a password.

My error thank you.
Don't look at the Sun.

agent_smith

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Re: Term Post Eye Tiable i.e. PET
« Reply #6 on: January 15, 2021, 04:32:51 AM »
Greeting jarnos:
Quote
My definition is somewhat different:
Feel free to invent your own theoretical body of work - and publish it.
This is how science progresses over a period of time.
Let me know when you have published - so I can download and read it.

In relation to the definition of 'PET':
Quote
E.g. a TIB knot may exist before forming the eye
The key point is whether any knot tying maneuvers are required (ie be pre-existing) before the eye is sized and formed.
If such maneuvers are a necessity, and the eye cannot be sized and formed without such a pre-existing condition, then the knot cannot be deserving of the title of 'PET'.
From a technical standpoint, your alleged pre-existing 'TIB' knot could be tied after the eye has been sized and formed.
A 'TIB' structure is equivalent to the 'unknot' (ie an unknotted length of rope).

Quote
some other maneuvers such as forming a loop (like in case of a bowline) may be needed before forming the eye.
With regard to a 'Bowline', it is not a pre-existing condition that a loop is formed before attempting to size and form the eye.

...

In terms of the history of the invention and use of the term 'PET'; it was likely that grandmasters such as Xarax and Dan Lehman evolved the concept either independently of each other or in one of their great debates... not sure which.

Mobius also appeared to be motivated to add a dimensional object to qualify the definition of 'PET'.
I believe that it isn't necessary to add such a qualifier.
However, one could state that; "By default, the eye of a PET knot can be formed through a ring".
Although, the inclusion of a 'ring' to qualify the definition is not essential to understanding.

...

You appear to be struggling to understand many basic concepts...
Not sure why?

jarnos

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Re: Term Post Eye Tiable i.e. PET
« Reply #7 on: January 15, 2021, 11:42:31 AM »
The key point is whether any knot tying maneuvers are required (ie be pre-existing) before the eye is sized and formed.
If such maneuvers are a necessity, and the eye cannot be sized and formed without such a pre-existing condition, then the knot cannot be deserving of the title of 'PET'.
From a technical standpoint, your alleged pre-existing 'TIB' knot could be tied after the eye has been sized and formed.

Could you please be more exact about what you mean by forming and sizing an eye? One could think that the whole process of tying an eye knot is forming and sizing of an eye. Forming an eye is not the same thing as forming a bight or a loop, right?

In case of a bowline, you could start by tying a loose overhand knot and capsize it later. Anyway, when the knot is ready and you follow the cord from the standing part into the knot, the first thing the cord does is a loop before you get to the eye part of the knot.

Quote
A 'TIB' structure is equivalent to the 'unknot' (ie an unknotted length of rope).

What is your definition of equivalence relation between knots? Do you regard tying a TIB knot equivalent of tying nothing? In mathematical knot theory unknot is like a circle, an endless closed loop.
Jarno Suni

jarnos

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Re: Term Post Eye Tiable i.e. PET
« Reply #8 on: January 15, 2021, 12:07:48 PM »
To tie the knot in the photo, you could first tie a TIB Span loop (ABoK#1049) and then tie the working part to its eye (loop).

I would say the knot in the photo is PET in respect of the eye marked by the green loop. The knot has also two other eyes marked by black and white loops. The green loop (if big enough) could be moved to meet the white and the black one. If the bight marked by the green loop was much shorter, the tip of the respective eye would be located at the region of the other eyes.
Jarno Suni

jarnos

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Re: Term Post Eye Tiable i.e. PET
« Reply #9 on: January 15, 2021, 05:54:02 PM »
Maybe post-eye-tiable is not the best term for what I am looking for. The key thing is that you do not have to thread the part of the cord that becomes the eye through/behind anything except maybe the object that the eye is connected to. It is handy to use that kind of knot especially, if the eye has to be very large.
Jarno Suni

SS369

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Re: Term Post Eye Tiable i.e. PET
« Reply #10 on: January 15, 2021, 07:40:53 PM »
Maybe post-eye-tiable is not the best term for what I am looking for. The key thing is that you do not have to thread the part of the cord that becomes the eye through/behind anything except maybe the object that the eye is connected to. It is handy to use that kind of knot especially, if the eye has to be very large.

Hi Jarnos.

I am somewhat confused now. >>> ? The key thing is that you do not have to thread the part of the cord that becomes the eye through/behind anything except maybe the object that the eye is connected to.?<<<

How else is the eye to be formed when using an object that the eye is going to be around or through, such as a ring, tree, spar, pole, or anything?

With some post (after) eye tiable knots, the eye is easily sized before tying the core that finishes the knot.

I can form a bowline with a very large eye or adjust it to a very small eye.

So, is there a communication challenge or typos to be considered?

SS


jarnos

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Re: Term Post Eye Tiable i.e. PET
« Reply #11 on: January 15, 2021, 09:40:42 PM »
How else is the eye to be formed when using an object that the eye is going to be around or through, such as a ring, tree, spar, pole, or anything?

With some post (after) eye tiable knots, the eye is easily sized before tying the core that finishes the knot.

Hi SS,

Some part of (the cord that will become) the eye may have to be threaded through a ring, if the eye is to be tied to a ring, but the knot as such could be made without any additional object.

You can form and size a bight, or U turn, but I would call it an eye only after it has been somehow connected to the standing part or to an inline knot so that the unity encloses a region. It is unnecessary to require that no knot tying maneuvers must be made before accomplish such a closed region.
Jarno Suni

Dan_Lehman

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Re: Term Post Eye Tiable i.e. PET
« Reply #12 on: January 15, 2021, 11:40:55 PM »
?!  There is a lot of effort here expended to take
something that is simple and effective and turn
it into ... --I don't know what.

Quote
no knot except maybe a tiable-in-a-bight knot is needed
before the first threading that forms the eye of the knot
and that threading must make the eye smaller,
and a bight is not threaded over the eye later on in the tying process.
How would an NSUE (=TIB) knot be "needed",
as that character of it ensures that it can be put
in ... whenever!?

The simple point is that one has NO KNOT in the line,
and will (be able to) make the eye forming --e.g., the
putting the line through a mooring ring on the quay--
in this state, "size" it to whatever size appropriate,
AND THEN tie the knot.
--a simple and sometimes important quality.


--dl*
====

jarnos

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Re: Term Post Eye Tiable i.e. PET
« Reply #13 on: January 16, 2021, 01:48:53 AM »
?!  There is a lot of effort here expended to take
something that is simple and effective and turn
it into ... --I don't know what.

This is rather academic, but I suppose it can be discussed about in this sub forum.

Quote
How would an NSUE (=TIB) knot be "needed",
as that character of it ensures that it can be put
in ... whenever!?

Well, take a look at the knot in reply #8. You can not tie the TIB part of the knot after you have tied the returning eye-leg to it, but you can tie it even before forming the bight/collar for the eye.

Quote
The simple point is that one has NO KNOT in the line,
and will (be able to) make the eye forming --e.g., the
putting the line through a mooring ring on the quay--
in this state, "size" it to whatever size appropriate,
AND THEN tie the knot.
--a simple and sometimes important quality.

That is practical point of view. Maybe call it post collar tiable eye knot, then :)

Other definition would be that it is an eye knot where no non-TIB knot is required before the eye part. Do we have a term for non-TIB knot i.e. for a knot that requires access to the working end?
« Last Edit: January 16, 2021, 08:51:11 PM by jarnos »
Jarno Suni

jarnos

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Re: Term Post Eye Tiable i.e. PET
« Reply #14 on: January 16, 2021, 09:40:14 PM »
Do we have a term for non-TIB knot i.e. for a knot that requires access to the working end?

If not, I think we could use terms like tying requires extremity (TRE) or end knot.
And maybe middle knot for a TIB knot, respectively; using an end knot in the middle of a very long cord would be unpractical.

Another way would be to use agent_smith's terminology: unknot for middle knot.
Then end knot would be something like proper knot. This might be confusing for as middle knots can be substantial knots, too, in practice.
Jarno Suni