Thank you for your answer, Russel.

When a code path takes advantage of a jet, does the Simplicity code still
need to be publicly available/visible in the blockchain? I imagine that for
big algorithms (say for example EDCA verification/SHA256 hashing etc), it
would take up a lot of space in the blockchain.
Is there any way to mitigate this?

I guess in a softfork for a jet, the Simplicity code for a jet could be
defined as "consensus", instead of needed to be provided within every
script output.
When the Simplicity interpretor encounters an expression that has a jet, it
would run the C/Assembly code instead of interpreting the Simplicity code.
By formal verification we would be sure they match.

Greetings
Hampus

2017-11-03 2:10 GMT+01:00 Russell O'Connor via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org>:

> Hi Jose,
>
> Jets are briefly discussed in section 3.4 of https://blockstream.com/
> simplicity.pdf
>
> The idea is that we can recognize some set of popular Simplicity
> expressions, and when the Simplicity interpreter encounters one of these
> expressions it can skip over the Simplicity interpreter and instead
> directly evaluate the function using specialized C or assembly code.
>
> For example, when the Simplicity interpreter encounters the Simplicity
> expression for ECDSA verification, it might directly call into libsecp
> rather than continuing the ECDSA verification using interpreted Simplicity.
>
> HTH.
>
>
> On Nov 2, 2017 18:35, "JOSE FEMENIAS CAÑUELO via bitcoin-dev" <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
>
> Hi,
>
> I am trying to follow this Simplicity proposal and I am seeing all over
> references to ‘jets’, but I haven’t been able to find any good reference to
> it.
> Can anyone give me a brief explanation and or a link pointing to this
> feature?
> Thanks
>
> On 31 Oct 2017, at 22:01, bitcoin-dev-request@lists.linuxfoundation.org
> wrote:
>
> The plan is that discounted jets will be explicitly labeled as jets in the
> commitment.  If you can provide a Merkle path from the root to a node that
> is an explicit jet, but that jet isn't among the finite number of known
> discounted jets,
>
>
>
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