Convoy conundrum...

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FxFocus
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Convoy conundrum...

#1 Post by FxFocus » Sat Jun 27, 2020 9:51 am

Hope the following makes sense.

A Bel attack F Edi via convoy Nth sea
F Norw sea sup A Bel to Edi
F Lon attack F Nth sea
F Edi sup F Lon to Nth sea

So F Edi is supporting an attack on the fleet that is convoying an attack on itself..!

Does the convoyed attack succeed?

Claesar
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Re: Convoy conundrum...

#2 Post by Claesar » Sat Jun 27, 2020 10:36 am

These situations are very complicated, but I believe DATC rules Nth is dislodged so the convoy can't cut the support.

Squigs would know for sure.

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Re: Convoy conundrum...

#3 Post by FxFocus » Sat Jun 27, 2020 10:50 am

Your answer caused me to look up the DATC where I found the following extract from test case 6.F.14.

"This situation depends on how paradoxes are handled (see issue (4.A.2). In case of the 'All Hold' rule (fully applied, not just as "backup" rule), both the movement of the English fleet in Wales as the France convoy in Brest are part of the paradox and fail. In all other rules of paradoxical convoys (including the Szykman rule which I prefer), the support of London is not cut. That means that the fleet in the English Channel is dislodged."

So which rule applies here on webdiplomacy?

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Re: Convoy conundrum...

#4 Post by RoganJosh » Sat Jun 27, 2020 1:51 pm

http://webdiplomacy.net/datc.php

Scroll down to 6.F.14. - convoying fleet will be dislodged.
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Re: Convoy conundrum...

#5 Post by David E. Cohen » Sat Jun 27, 2020 4:30 pm

There is no convoy paradox here. I can tell because I have reviewed the orders in the opening post and not gotten a headache. F North Sea is dislodged 1v2.

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Re: Convoy conundrum...

#6 Post by jay65536 » Sat Jun 27, 2020 5:49 pm

Not a paradox. There is a specific rule that covers this. The support is not cut, and the convoy fails.

It would be a paradox if there were two other fleets, such as Den and Hol, that were also attacking Nth. In that case, a ruling that the convoy fails means the fleet should not be dislodged, but ruling that it succeeds means it should be.

Your example is much more clear-cut than that.
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Re: Convoy conundrum...

#7 Post by Squigs44 » Sun Jun 28, 2020 5:45 am

This question looks resolved, but since Claesar name dropped me, I guess I'll give my "authoritative" answer here to clear up any confusion.

As pointed out by almost everyone, the convoy fails.
As pointed out by several people, 6.F.14 of the DATC covers this issue, although the scenarios are not exactly the same.
The key debate here is whether this qualifies as a convoy paradox or not, and the answer is that it is indeed a convoy paradox. You know it is a convoy paradox because if we were to assume that the convoy is successful, then the support given by Edi would be cut and North Sea would not be dislodged. This creates two consistent but opposing possible adjudications, hence the paradox. In the case of convoy paradoxes, the convoy pretty much always fails and the support is not cut.
The example given by jay65536 is called Pandins Paradox and is a much more interesting scenario (6.F.16 of the DATC).
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Re: Convoy conundrum...

#8 Post by David E. Cohen » Sun Jun 28, 2020 11:16 am

Hello Squigs44, I disagree with your definition of the classification of the scenario as a convoy paradox. It lacks cyclicality.

Aaaaaand, now my head is starting to hurt. :eyeroll:

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Re: Convoy conundrum...

#9 Post by Squigs44 » Sun Jun 28, 2020 8:51 pm

I'm working straight off of the DATC. In fact, the DATC says:
"The most common paradox is when the attacked unit supports an attack on one of the convoying fleets."
Not only does the DATC state that this is a paradox, it is the most common. I think what you are trying to assert is that a convoy paradox must involve a cycle where no consistent resolution can occur. While that is a convoy paradox, it is not the only kind of paradox. You can also have convoy paradoxes with multiple consistent resolutions. Take for example DATC 6.F.22 and 6.F.23. They are similar scenarios, but in 22 we have two possible resolutions and in 23 we have no possible resolution due to a cycle. Both are considered convoy paradoxes by the DATC (which is what I'm using in any adjudication based discussion).

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Re: Convoy conundrum...

#10 Post by David E. Cohen » Sun Jun 28, 2020 10:22 pm

Per the rulebook, there is only one correct adjudication. Since it is dealt with by the rulebook, there is no paradox.

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Re: Convoy conundrum...

#11 Post by Squigs44 » Sun Jun 28, 2020 11:04 pm

Also from the DATC:
Some people argue that some situations are not convoy paradoxes, since the rules give a resolution for those situations. Hence, for a proper discussion on paradoxes, rule XII.5 of the 1971, 1976, 1982 and 1992 rulebooks and the rule on the top of page 16 of the 2000 rulebook, should not be taken into account in the above definition of a paradox.

Again, I don't take issue with your assessment of the situation, the rules do specifically address this situation, but if we are trying to be consistent in terminology, the DATC has defined this as a convoy paradox.

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Re: Convoy conundrum...

#12 Post by David E. Cohen » Sun Jun 28, 2020 11:27 pm

The actual rule from the rulebook is as follows: "A convoyed Army does not cut the support of a unit supporting an attack against one of the Fleets necessary of the Army to convoy. This is a tricky and rare situation, but without this rule (Using Diagram 30 as an example), a paradox may occur." Note that the rulebook itself is excluding this situation from the realm of paradox.

I have great respect for Lucas Kruijswijk and his work developing the DATC. It is a very useful and widely used tool. But that is all it is. A tool. It is not the rulebook.

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Re: Convoy conundrum...

#13 Post by Squigs44 » Sun Jun 28, 2020 11:52 pm

Okay well at this point its a disagreement on semantics. There are two schools of thought here. I'll stand by the DATCs definition and interpretation of the rulebook.

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Re: Convoy conundrum...

#14 Post by jay65536 » Mon Jun 29, 2020 7:01 pm

David E. Cohen wrote:
Sun Jun 28, 2020 11:27 pm
The actual rule from the rulebook is as follows: "A convoyed Army does not cut the support of a unit supporting an attack against one of the Fleets necessary of the Army to convoy. This is a tricky and rare situation, but without this rule (Using Diagram 30 as an example), a paradox may occur." Note that the rulebook itself is excluding this situation from the realm of paradox.
Reading this discussion, it seems you guys might be talking past each other a bit.

The situation that the rulebook is excluding from being a paradox is this one:

A Bel-Edi, F Nth C Bel-Edi, F Lon-Nth, F Edi S Lon-Nth

This is the situation in the OP minus the Nwg fleet. Before the addition of this rule to the rulebook, this was a paradox. Now it is clearly not--the Nth fleet is dislodged and the army does not move.

I think Squigs is claiming that adding the Nwg fleet to support the convoyed move makes this a paradox, because you could (unsuccessfully, in my opinion, try to) argue that this rule is no longer controlling. Under this argument, the controlling rule would be the one that says a dislodged unit can't support anything at all. The argument goes that because Edi is being attacked with enough support to dislodge it, it can't support the attack that would dislodge the convoying fleet.

The problem with this argument, as I see it, is that it's circular. You have to assume the convoy succeeds in order to prove it succeeds. You also have to assume that Nwg's support order is valid before you check whether Bel's move order is valid--which is something we would never do in any other adjudication.

The circular and forced nature of this alleged second possible adjudication is why this shouldn't be considered a paradox.

As a sidenote, it seems to me that ruling that convoys should always fail in paradoxes in order to resolve them is far from a standard adjudication. Maybe it is the one used by online adjudicators, but I would not rule this way in my house games.

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Re: Convoy conundrum...

#15 Post by RoganJosh » Mon Jun 29, 2020 8:28 pm

Squigs is not "claiming" that this is a paradox. He is only pointing out that this is classified as a paradox in DATC.

You should probably read the whole thing, before you comment any further. Because, at the moment, you mainly come across as ill-informed.
http://web.inter.nl.net/users/L.B.Kruijswijk/

The rule you are referring to is incomplete, and insufficient to resolve all ambiguous and condratictory convoy situations (for simplicity, these are all referred to as 'paradoxes' in DATC). Everyone agrees on what the resolution should be in the example that started this thread. But that rule in the rulebook (which has been altered in more or less every iteration of the rules) is far from satisfactory.

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Re: Convoy conundrum...

#16 Post by David E. Cohen » Mon Jun 29, 2020 10:17 pm

On that I can agree. There are numerous convoy paradoxes, set forth in jaw dropping/mind numbing detail in the DATC, which are not handled at all by the rulebook. Fortunately; they come up very, very rarely in actual play.

Ugh. Got another headache thinking about paradoxes.

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Re: Convoy conundrum...

#17 Post by FxFocus » Tue Jun 30, 2020 9:44 am

Thanks everyone for contributing...

Discussions regards paradox were interesting but in this instance I was only interested in how the webdiplomacy online judge would resolve it.

Seems the convoy would fail and the army not move..!

Thanks again to everyone. :-)
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Re: Convoy conundrum...

#18 Post by David E. Cohen » Tue Jun 30, 2020 2:52 pm

I object to the initial poster objecting to the hijacking of his thread.
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Re: Convoy conundrum...

#19 Post by FxFocus » Wed Jul 01, 2020 4:59 am

David E. Cohen wrote:
Tue Jun 30, 2020 2:52 pm
I object to the initial poster objecting to the hijacking of his thread.
Sorry if I gave the impression I was objecting to anything lol.
I wasn't being facetious, I did find the whole discussion interesting.

I know you said this tongue in cheek but I was merely wanting to make the point that putting rulebooks and DATC aside it's the judge implementation that resolves the orders. Whether or not the judge got it right is of interest but doesn't change the outcome in the short term.

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Re: Convoy conundrum...

#20 Post by JF1981 » Wed Jul 08, 2020 8:21 pm

So here is one im not sure about...

Army in Mars being convoyed by GoL fleet to Rome where there is an italian army. Why can't the Tyr fleet I own support this move?

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