Are direct mechanisms always truthful?
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I am very new to mechanism design so I am a bit lost among the concepts, even the most basic ones.
One thing that is not clear to me is the concept of direct mechanism and its relationship with the revelation principle.
From what I got a direct mechanism is a mechanisms, in which, instead of messages, the agents report their preference/type. Are we assuming this is a truthful report?
I am asking that because the revelation principle is stated as "anything that can be accomplished by any mechanism can actually be accomplished by a direct revelation mechanism that is individual rational and incentive compatible" in this notes but as "a social choice function can be implemented by an arbitrary mechanism (i.e. if that mechanism has an equilibrium outcome that corresponds to the outcome of the social choice function), then the same function can be implemented by an incentive-compatible-direct-mechanism (i.e. in which players truthfully report type) with the same equilibrium outcome (payoffs)." on Wikipedia.
So I don't get if truthfulness is implied by the direct mechanism or if it is an additional requirement.
game-theory mechanism-design
asked 4 hours ago
Alessandro
436421
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up vote
3
down vote
favorite
I am very new to mechanism design so I am a bit lost among the concepts, even the most basic ones.
One thing that is not clear to me is the concept of direct mechanism and its relationship with the revelation principle.
From what I got a direct mechanism is a mechanisms, in which, instead of messages, the agents report their preference/type. Are we assuming this is a truthful report?
I am asking that because the revelation principle is stated as "anything that can be accomplished by any mechanism can actually be accomplished by a direct revelation mechanism that is individual rational and incentive compatible" in this notes but as "a social choice function can be implemented by an arbitrary mechanism (i.e. if that mechanism has an equilibrium outcome that corresponds to the outcome of the social choice function), then the same function can be implemented by an incentive-compatible-direct-mechanism (i.e. in which players truthfully report type) with the same equilibrium outcome (payoffs)." on Wikipedia.
So I don't get if truthfulness is implied by the direct mechanism or if it is an additional requirement.
game-theory mechanism-design
asked 4 hours ago
Alessandro
436421
add a comment |
up vote
3
down vote
favorite
up vote
3
down vote
favorite
I am very new to mechanism design so I am a bit lost among the concepts, even the most basic ones.
One thing that is not clear to me is the concept of direct mechanism and its relationship with the revelation principle.
From what I got a direct mechanism is a mechanisms, in which, instead of messages, the agents report their preference/type. Are we assuming this is a truthful report?
I am asking that because the revelation principle is stated as "anything that can be accomplished by any mechanism can actually be accomplished by a direct revelation mechanism that is individual rational and incentive compatible" in this notes but as "a social choice function can be implemented by an arbitrary mechanism (i.e. if that mechanism has an equilibrium outcome that corresponds to the outcome of the social choice function), then the same function can be implemented by an incentive-compatible-direct-mechanism (i.e. in which players truthfully report type) with the same equilibrium outcome (payoffs)." on Wikipedia.
So I don't get if truthfulness is implied by the direct mechanism or if it is an additional requirement.
game-theory mechanism-design
asked 4 hours ago
Alessandro
436421
I am very new to mechanism design so I am a bit lost among the concepts, even the most basic ones.
One thing that is not clear to me is the concept of direct mechanism and its relationship with the revelation principle.
From what I got a direct mechanism is a mechanisms, in which, instead of messages, the agents report their preference/type. Are we assuming this is a truthful report?
I am asking that because the revelation principle is stated as "anything that can be accomplished by any mechanism can actually be accomplished by a direct revelation mechanism that is individual rational and incentive compatible" in this notes but as "a social choice function can be implemented by an arbitrary mechanism (i.e. if that mechanism has an equilibrium outcome that corresponds to the outcome of the social choice function), then the same function can be implemented by an incentive-compatible-direct-mechanism (i.e. in which players truthfully report type) with the same equilibrium outcome (payoffs)." on Wikipedia.
So I don't get if truthfulness is implied by the direct mechanism or if it is an additional requirement.
game-theory mechanism-design
game-theory mechanism-design
asked 4 hours ago
Alessandro
436421
asked 4 hours ago
Alessandro
436421
edited 4 hours ago
asked 4 hours ago
Alessandro
436421
asked 4 hours ago
Alessandro
436421
asked 4 hours ago
Alessandro
436421
436421
add a comment |
add a comment |
1 Answer
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Incentive compatible here means that you have no incentive to lie. A direct mechanism that is not incentive compatible would entice some agents to report a false type.
answered 3 hours ago
denesp
12.1k32047
Thanks! Thus, for example, the revelation principle in dominant strategies is saying if a social choice function is implementable, than it is implementable using a direct mechanism, i.e. truth-telling is always a dominant strategy. Is it the right way to think about it?
– Alessandro
3 hours ago
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
Incentive compatible here means that you have no incentive to lie. A direct mechanism that is not incentive compatible would entice some agents to report a false type.
answered 3 hours ago
denesp
12.1k32047
Thanks! Thus, for example, the revelation principle in dominant strategies is saying if a social choice function is implementable, than it is implementable using a direct mechanism, i.e. truth-telling is always a dominant strategy. Is it the right way to think about it?
– Alessandro
3 hours ago
add a comment |
up vote
3
down vote
Incentive compatible here means that you have no incentive to lie. A direct mechanism that is not incentive compatible would entice some agents to report a false type.
answered 3 hours ago
denesp
12.1k32047
Thanks! Thus, for example, the revelation principle in dominant strategies is saying if a social choice function is implementable, than it is implementable using a direct mechanism, i.e. truth-telling is always a dominant strategy. Is it the right way to think about it?
– Alessandro
3 hours ago
add a comment |
up vote
3
down vote
up vote
3
down vote
Incentive compatible here means that you have no incentive to lie. A direct mechanism that is not incentive compatible would entice some agents to report a false type.
answered 3 hours ago
denesp
12.1k32047
Incentive compatible here means that you have no incentive to lie. A direct mechanism that is not incentive compatible would entice some agents to report a false type.
answered 3 hours ago
denesp
12.1k32047
answered 3 hours ago
denesp
12.1k32047
answered 3 hours ago
denesp
12.1k32047
answered 3 hours ago
denesp
12.1k32047
12.1k32047
Thanks! Thus, for example, the revelation principle in dominant strategies is saying if a social choice function is implementable, than it is implementable using a direct mechanism, i.e. truth-telling is always a dominant strategy. Is it the right way to think about it?
– Alessandro
3 hours ago
add a comment |
Thanks! Thus, for example, the revelation principle in dominant strategies is saying if a social choice function is implementable, than it is implementable using a direct mechanism, i.e. truth-telling is always a dominant strategy. Is it the right way to think about it?
– Alessandro
3 hours ago
Thanks! Thus, for example, the revelation principle in dominant strategies is saying if a social choice function is implementable, than it is implementable using a direct mechanism, i.e. truth-telling is always a dominant strategy. Is it the right way to think about it?
– Alessandro
3 hours ago
Thanks! Thus, for example, the revelation principle in dominant strategies is saying if a social choice function is implementable, than it is implementable using a direct mechanism, i.e. truth-telling is always a dominant strategy. Is it the right way to think about it?
– Alessandro
3 hours ago
add a comment |
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