## Divide By 0

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stackingzerglings
Joined Dec 2007
60 Posts
I was wondering if there are any ways to cause a divide by zero error in magic. If so, what would happen?

Aside from the obvious...
nereusren
Joined Jul 2003
310 Posts
Nothing too exciting... as an undefined quantity, the result would be treated as zero.

104.2. If anything needs to use a number that can't be determined, either as a result or in a calculation, it uses 0 instead.

JohnnyComeLately
Joined Oct 2008
2903 Posts
I guess you could make the 3s in Pox 0s with multiple Look At Me, I'm R&amp;D, but Un-sets aren't covered by regular rules, so I have no idea what would happen.

The universe would probably collapse.
inori
Joined Feb 2005
3556 Posts
When playing Fireball, it's possible to choose zero target creatures ("any number" includes zero). You're thus dividing X damage (X can still be nonzero if you just like wasting mana) among zero target creatures. Nothing special happens even though Fireball will try to deal X / 0 = {undefined} damage to each target, since you don't have any actual targets to deal {undefined} damage to anyway.
usasatsui
Joined Aug 2008
301 Posts
When playing Fireball, it's possible to choose zero target creatures ("any number" includes zero). You're thus dividing X damage (X can still be nonzero if you just like wasting mana) among zero target creatures. Nothing special happens even though Fireball will try to deal X / 0 = {undefined} damage to each target, since you don't have any actual targets to deal {undefined} damage to anyway.

...I don't think that works. "Any number of targets" implies you need at least one.

Besides, if you choose 0, you have no targets...and the spell requires them, therefore you can't legally play the spell.
teliot
Joined Dec 2007
2685 Posts
I guess if you play Dwarven Catapult when your opponent has no creatures?

I think I know what would happen. Namely, nothing would happen...
jeff-heikkinen
Joined Aug 2001
9624 Posts
...I don't think that works. "Any number of targets" implies you need at least one.

It "implies" nothing of the sort, and says the opposite straight out. "Any number" means "any number", not something else.

Besides, if you choose 0, you have no targets...and the spell requires them, therefore you can't legally play the spell.

A spell can't be played without naming a full complement of legal targets, but I don't see how you conclude from that that a zero-target Fireball is unplayable (any more than a Wrath or any other spell with no targets). A spell requires the number of targets it says it requires, not some other number.

Jeff Heikkinen

I have permanently left these forums.

Bad moderation decisions were the last straw, but there were other factors too.

But if you see this and are into tabletop RPGs and/or Final Fantasy and similar JRPGs, why not check out my site at philosoraptorgames.com?

guest128241469_dup
Joined Apr 2009
13 Posts
ii
guest128241469_dup
Joined Apr 2009
13 Posts
It "implies" nothing of the sort, and says the opposite straight out. "Any number" means "any number", not something else.

A spell can't be played without naming a full complement of legal targets, but I don't see how you conclude from that that a zero-target Fireball is unplayable (any more than a Wrath or any other spell with no targets). A spell requires the number of targets it says it requires, not some other number.

Are you serious. If the spell says target anywhere it needs at least 1 target, therefore you really can't play a fireball for 0 with no target/s. You can play a fireball for 0 all day long. You have to have at least one target to even announce it. Am I going crazy here?
HendrikHaese
Joined Jun 2008
1291 Posts
Are you serious. If the spell says target anywhere it needs at least 1 target, therefore you really can't play a fireball for 0 with no target/s. You can play a fireball for 0 all day long. You have to have at least one target to even announce it. Am I going crazy here?

We are serious. Look at Tezzeret the Seeker and the appropriate ruling:
10/1/2008 The first ability can target zero, one, or two artifacts. You may play it with no targets just to put a loyalty counter on Tezzeret.

The matter at hand is quite similar. "Any number of targets" means exactly that. Any number. That number may be zero.
DCI L2 Judge "When nothing remains, everything is equally possible." - One With Nothing
guest128241469_dup
Joined Apr 2009
13 Posts
We are serious. Look at Tezzeret the Seeker and the appropriate ruling:

The matter at hand is quite similar. "Any number of targets" means exactly that. Any number. That number may be zero.

Nope. UP to means up to.

Fireball has to have at least 1 target. even if it has to be the opponent. Tezzy is a completely different wording. You're comparing apples and oranges.
Kedar
Joined Sep 2007
6823 Posts
Nope. UP to means up to.

Fireball has to have at least 1 target. even if it has to be the opponent. Tezzy is a completely different wording. You're comparing apples and oranges.

Is zero a number? Yes? Then it is part of the set that defines 'any number.' Meaning it can be chosen just to play Fireball for and add to a storm count, if one desired to do so.

guest128241469_dup
Joined Apr 2009
13 Posts
Is zero a number? Yes? Then it is 'any number.' Meaning it can be chosen just to play Fireball for and add to a storm count, if one desired to do so.

that fireball is still targeting something because it has to. It would be the player if there are no creatures. Are you guys nuts?
guest128241469_dup
Joined Apr 2009
13 Posts
If there is no creatures it has to target a player, if there isn't a player to target, you can't cast the spell, right?
cyphern
Joined Jan 2003
19354 Posts
Are you guys nuts?

I like to think i am. The jury is still out though.
that fireball is still targeting something because it has to. It would be the player if there are no creatures.

In any event, i side with our guest here for two reasons. First, the following rule:
104.1b Most of the time, the Magic game uses only positive numbers. You can’t choose a negative number, deal negative damage, gain negative life, and so on. However, it’s possible for a game value, such as a creature’s power, to be less than zero. If a calculation or comparison that would determine the result of an effect needs to use a negative value, it does so. If such a calculation yields a negative number, zero is used instead, unless that effect sets a player’s life total to a specific value, sets a creature’s power or toughness to a specific value, or otherwise modifies a creature’s power or toughness.

And secondly, the precedent set by Arc Lightning (see its 2nd official ruling).
HendrikHaese
Joined Jun 2008
1291 Posts
that fireball is still targeting something because it has to. It would be the player if there are no creatures. Are you guys nuts?

Yes, quite possibly we are nuts. But still we are right. Usually it won't make the slightest bit of difference to have a Fireball deal 0 damage to one target rather than having it target zero targets. It is still legal. Imagine there are no creatures in play and you are both Runed Haloed from Fireball. You can still announce and play Fireball targeting zero creatures and zero players, just to have that storm count go up by one.

Edit: Hm. Good catch there with the precedent ruling set by Arc Lightning, cyphern. I wonder if this ruling is still accurate...
DCI L2 Judge "When nothing remains, everything is equally possible." - One With Nothing
Kedar
Joined Sep 2007
6823 Posts
that fireball is still targeting something because it has to. It would be the player if there are no creatures. Are you guys nuts?

Are you a troll?

Seriously, are you? Because you seem to wish to argue despite everyone telling you you're wrong, including someone who is huge on numbers.

The set of all numbers that defines the phrase 'any number' is [-inf,inf] (or maybe (-inf,inf), depending on if you count infinity as a number, but that's not the point). 0 falls between those two extremes, and when it comes to choosing targets, is the first valid choice for anything that asks for 'up to X' or 'any number of' targets.

guest128241469_dup
Joined Apr 2009
13 Posts
Yes, quite possibly we are nuts. But still we are right. Usually it won't make the slightest bit of difference to have a Fireball deal 0 damage to one target rather than having it target zero targets. It is still legal. Imagine there are no creatures in play and you are both Runed Haloed from Fireball. You can still announce and play Fireball targeting zero creatures and zero players, just to have that storm count go up by one.

No I highly doubt you could play the fireball in that situation it has to has to has to have at least 1 target.
guest128241469_dup
Joined Apr 2009
13 Posts
Are you a troll?

Seriously, are you? Because you seem to wish to argue despite everyone telling you you're wrong, including someone who is huge on numbers.

The set of all numbers that defines the phrase 'any number' is [-inf,inf] (or maybe (-inf,inf), depending on if you count infinity as a number, but that's not the point). 0 falls between those two extremes, and when it comes to choosing targets, is the first valid choice for anything that asks for 'up to X' or 'any number of' targets.

AM I a troll? Do you always insult people in real life?

You can not cast a fireball without at least 1 target. that's the truth. learn some rules.
cyphern
Joined Jan 2003
19354 Posts
No I highly doubt you could play the fireball in that situation it has to has to has to have at least 1 target.
[...]
You can not cast a fireball without at least 1 target. that's the truth. learn some rules.

Assertions don't do any good, nor do intuitive explanations.
guest128241469_dup
Joined Apr 2009
13 Posts
Well If anything I have helped you learn something today. Even though you swear you're right. You CAN NOT cast a fireball with zero targets. It has to have one. If there are nor creatures, it's a player. if there are no players IT CAN NOT BE CAST. have a good day.
cyphern
Joined Jan 2003
19354 Posts
Well If anything I have helped you learn something today. Even though you swear you're right. You CAN NOT cast a fireball with zero targets. It has to have one. If there are nor creatures, it's a player. if there are no players IT CAN NOT BE CAST. have a good day.

I started on your side of this discussion, providing evidence to back up your case, but now you have taken to bald and unsupported assertions, and a dismissive attitude, making it evident that you aren't interested in determining the truth.

Anyway, in the hopes of continuing this discussion with those that are actually knowledgeable about the rules of the game, is the ruling on Arc lightning wrong?

EDIT: everyone just ignore the troll please.
guest128241469_dup
Joined Apr 2009
13 Posts
I started on your side of this discussion, providing evidence to back up your case, but now you have taken to bald and unsupported assertions, and a dismissive attitude, making it evident that you aren't interested in determining the truth.

Anyway, in the hopes of continuing this discussion with those that are actually knowledgeable about the rules of the game, is the ruling on Arc lightning wrong?

EDIT: everyone just ignore the troll please.Because he is right and we can't stand it

FYP
Kedar
Joined Sep 2007
6823 Posts
I started on your side of this discussion, providing evidence to back up your case, but now you have taken to bald and unsupported assertions, and a dismissive attitude, making it evident that you aren't interested in determining the truth.

Anyway, in the hopes of continuing this discussion with those that are actually knowledgeable about the rules of the game, is the ruling on Arc lightning wrong?

Considering the date on the ruling, I would be interested in learning that answer as well; however, to me, it seems counter-intuitive that 'any number' would not include 'zero' while 'up to' will, because 'up to' is a shorthand for 'any number up to X,' but because everyone knows the functionality, they can shorthand it with simply putting 'up to.'

@Guest: Provide us proof that you are right, sir/ma'am, and we will concede the point. However, the rule cyphern quoted does nothing to prove the argument one way or the other, and the date of the ruling for Arc Lightning means the ruling might be wrong and out of date, so we will have to see.

I will say again, however, that for 'up to' to be able to include zero but 'any number' to not be able to do so is not likely, though I will admit if I am wrong (if I am wrong). Can you say that you will do the same?

guest128241469_dup
Joined Apr 2009
13 Posts

Considering the date on the ruling, I would be interested in learning that answer as well; however, to me, it seems counter-intuitive that 'any number' would not include 'zero' while 'up to' will, because 'up to' is a shorthand for 'any number up to X,' but because everyone knows the functionality, they can shorthand it with simply putting 'up to.'

@Guest: Provide us proof that you are right, sir/ma'am, and we will concede the point. However, the rule cyphern quoted does nothing to prove the argument one way or the other, and the date of the ruling for Arc Lightning means the ruling might be wrong and out of date, so we will have to see.

I will say again, however, that for 'up to' to be able to include zero but 'any number' to not be able to do so is not likely, though I will admit if I am wrong (if I am wrong). Can you say that you will do the same?

Up to, means up to. It can be 0 up to value.

Fireball has to have at least1 target because it specifically asks. Therefore the number has to be at least 1. I don't know how to make it any more clear.
It's really simple.

it's apple and orange. Up to, and asking for a target are completely different.

You can cast fireball for 0. You must have 1 legal target. If there are no creatures, it's assumed it's a player. If their are no creature, players, or legal targets, it can not be cast. It can not be played at all.
cyphern
Joined Jan 2003
19354 Posts
I will say again, however, that for 'up to' to be able to include zero but 'any number' to not be able to do so is not likely, though I will admit if I am wrong (if I am wrong). Can you say that you will do the same?

I can think of many examples where "any number" must include zero as an option. For example, when resolving Ad Nauseam, you are clearly allowed to repeat it zero times. Thus it seems quite reasonable to me then that fireball could target 0 things. If we can determine that arc lightning has an obsolete ruling, then i retract my support of the "1 and up" position.
Kedar
Joined Sep 2007
6823 Posts
Up to means up to. It can be 0 up to value.

Fireball has to have at least1 target because it specifically asks. There fore the number has to be at least 1. I don't know how to make it any more clear.
It's really simple.

'up to' means 'any number up to X,' while 'any number' means 'any number' with no upper limit. 0 is part of the set that defines 'any number.'

You can't prove to me, in mathematical terms, that one couldn't choose 'zero' if asked to pick 'any number,' but I'm asking you to prove it to me in terms of Magic: the Gathering. As of yet, you've failed to do so because you've shown me nothing that says otherwise. The only thing that comes close is the possibly-outdated ruling on one card that cyphern showed us. Your 'intuition'--which is wrong in real math--is not proof of anything.

guest128241469_dup
Joined Apr 2009
13 Posts
'up to' means 'any number up to X,' while 'any number' means 'any number' with no upper limit. 0 is part of the set that defines 'any number.'

You can't prove to me, in mathematical terms, that one couldn't choose 'zero' if asked to pick 'any number,' but I'm asking you to prove it to me in terms of Magic: the Gathering. As of yet, you've failed to do so because you've shown me nothing that says otherwise. The only thing that comes close is the possibly-outdated ruling on one card that cyphern showed us. Your 'intuition'--which is wrong in real math--is not proof of anything.

U cannot target 0 things. How is this so hard.
Kedar
Joined Sep 2007
6823 Posts
U cannot target 0 things. How is this so hard.

Proof.

guest128241469_dup
Joined Apr 2009
13 Posts
I can think of many examples where "any number" must include zero as an option. For example, when resolving Ad Nauseam, you are clearly allowed to repeat it zero times. Thus it seems quite reasonable to me then that fireball could target 0 things. If we can determine that arc lightning has an obsolete ruling, then i retract my support of the "1 and up" position.

way to pull up a card with May in it. There are 0 instances of the word target in it.That is completely different than fireball, and Tezzy.
HendrikHaese
Joined Jun 2008
1291 Posts
I think I found the counter-example: Conflagrate:[INDENT]
If X is greater than 0, the number of targets must be at least 1 and at most X. If X is 0, the number of targets must also be 0.[/INDENT]
Is this sufficiently similar to Fireball to reason that a Fireball can (and in fact has to be) played targeting zero targets if you choose zero damage?
DCI L2 Judge "When nothing remains, everything is equally possible." - One With Nothing
magicalblender
Joined Apr 2007
816 Posts
This rule describes the step of playing a spell where you divide an effect, such as with fireball:
409.1e If the spell or ability requires the player to divide or distribute an effect (such as damage or counters) among one or more targets, or any number of untargeted objects or players, the player announces the division. Each of these targets, objects, or players must receive at least one of whatever is being divided.

It doesn't say outright that you can't pick 0 targets, but it implies that you may only pick one or more targets, and not zero.
cyphern
Joined Jan 2003
19354 Posts
I think there is a difference here between cards that divide damage between any number of targets, and those that do something else to any number of targets.

For example, look at Energy Arc. Its ruling indicates that you can choose 0 target creatures. A similar thing could be said of Cauldron Haze.

I would put forth that it is completely legal to select zero targets when it says "any number of target", and thus, fireball could in principle target zero creatures. The problem comes when you get to step 409.1e. You are then required to distribute damage to one or more of the targets, and if you selected 0 targets in 409.1c, then you cannot complete the step. Thus, you have played the spell illegally, and must undo playing the spell.

Ie, you can choose 0 targets, but since you cannot distribute damage to zero targets, fireball with X > 0 must have targets > 0, or it has been played illegally.
GoblinBasar
Joined Nov 2006
1005 Posts
But 409.1e doesn't apply at all in the case of Fireball, because Fireball does not ask a player to distribute anything; Fireball will distribute its love all on its own.

DCI Lvl 2 Judge

cyphern
Joined Jan 2003
19354 Posts
But 409.1e doesn't apply at all in the case of Fireball, because Fireball does not ask a player to distribute anything; Fireball will distribute its love all on its own.

You may not have any options about how to distribute the damage, but the spell still requires you to divide the damage. In fireball's case, you divide the damage "evenly, rounded down", whereas something like conflagrate has you divide it "as you choose".
condor
Joined Mar 2001
818 Posts
I was wondering if there are any ways to cause a divide by zero error in magic.

No. Magic only uses "divide" as in the sense of "separate a quantity into parts," not (directly) mathematical division. Sometimes math is implied, by "divide evenly," but it can't divide by zero. The effect will be telling you to do something to nothing, which is impossible and is ignored.
"Any number of targets" implies you need at least one.

"Any number" means "any number." Zero is a number.
In any event, i side with our guest here for two reasons. First, the following rule:
And secondly, the precedent set by Arc Lightning (see its 2nd official ruling).

I have no idea why you think that rule applies, but Arc Lightning is different. It is telling you to do an impossible action as part of playing a spell, which can't be ignored. It means you can't play the spell; the zero targets aren't prohibited per se, but the spell is. Fireball does not require you to choose amounts, so it can be played with zero targets (as currently worded).
cyphern
Joined Jan 2003
19354 Posts
I have no idea why you think that rule applies

Because 0 is not a positive number.

In any event, i've abandoned the position i had when i posted that.
condor
Joined Mar 2001
818 Posts
Because 0 is not a positive number.

"Most of the time, the _Magic_ game uses only positive numbers." But I think you will find that in the cases of interest here, Magic doesn't try to "use" zero even if you choose it. And if you read the whole rule, you will find is says you can't choose negative numbers.
cyphern
Joined Jan 2003
19354 Posts
"Most of the time, the _Magic_ game uses only positive numbers." But I think you will find that in the cases of interest here, Magic doesn't try to "use" zero even if you choose it. And if you read the whole rule, you will find is says you can't choose negative numbers.

I stopped considering the rule to be relevant several hours ago, as soon as i had looked into the issue more deeply. You stated that you had no idea why i could have thought the rule applied, and i simply explained why i had (note: past tense) thought that.
garld
Joined Nov 2008
127 Posts
Fireball is a targeted spell. Is there any debate on this point?

409.1c If the spell or ability requires any targets, the player first announces how many targets he or
she will choose (if the spell or ability has a variable number of targets), then announces his or
her choice of an appropriate player, object, or zone for each of those targets. A player can’t play
a spell or ability unless he or she chooses the required number of legal targets. The same target
can’t be chosen multiple times for any one instance of the word “target” on the spell or ability.
If the spell or ability uses the word “target” in multiple places, the same object, player, or zone
can be chosen once for each instance of the word “target” (as long as it fits the targeting
criteria)

Lets walk through trying to cast Fireball targeted at 0 targets.

Player: I announce Fireball, X=10, zero targets.
Game: Chose your appropriate 0 targets
Player: There are no appropriate targets, I can not target player, object or zone because I chose zero targets.
Game: Well then you can't play that then, you haven't targeted anything. Zero targets is not targeting anything.

So if you can't choose a target for a targeted spell...what happens? Well you can't play the spell and must back up.
Without an instance of at least one appropriate target, the spell cannot be announced.
cyphern
Joined Jan 2003
19354 Posts
Fireball is a targeted spell.

Only if targets have been chosen for it.
415.4. Spells and abilities that can have zero or more targets are targeted only if one or more targets have been chosen for them.

Player: I announce Fireball, X=10, zero targets.
Game: Chose your appropriate 0 targets
Player: There are no appropriate targets, I can not target player, object or zone because I chose zero targets.

Choosing 0 targets is trivially easy. Simply do nothing.