Verizon Public Policy on Netflix
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Mon Jul 21 12:47:34 UTC 2014
When exactly did we sign up for a discreet math course `-`
On 7/21/2014 午後 09:31, Michael Conlen wrote:
> On Jul 18, 2014, at 2:32 PM, Jay Ashworth <jra at baylink.com> wrote:
>> ----- Original Message -----
>>> From: "Owen DeLong" <owen at delong.com>
>>> But the part that will really bend your mind is when you realize that
>>> there is no such thing as "THE Internet".
>> "The Internet as "the largest equivalence class in the reflexive, transitive, symmetric closure of the relationship 'can be reached by an IP packet from'"
>> -- Seth Breidbart.
> I happen to like this idea but since we are getting picky and equivalence classes are a mathematical structure 'can be reached by an IP packet from’ is not an equivalence relation. I will use ~ as the relation and say that x ~ y if x can be reached by an IP packet from y
> In particular symmetry does not hold. a ~ b implies that a can be reached by b but it does not hold that b ~ a; either because of NAT or firewall or an asymmetric routing fault. It’s also true that transitivity does not hold, a ~ b and b ~ c does not imply that a ~ c for similar reasons.
> Therefore, the hypothesis that ‘can be reached by an IP packet from’ partitions the set of computers into equivalence classes fails.
> Perhaps if A is the set of computers then “The Internet” is the largest subset of AxA, say B subset AxA, such for (a, b) in B the three relations hold and the relation partitions B into a single equivalence class.
> That really doesn’t have the same ring to it though does it.
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