# [Iris-Club] pre-wp's definition: s, s1, and s2

Jeehoon Kang jeehoon.kang at sf.snu.ac.kr
Sat Aug 20 16:22:48 CEST 2016

Another point is that, "wp is defined as the fixed-point of a contractive
function," but I am not sure there is "the" fixed-point.  Previously in the
documentation it is only said that a contractive function has "a"
fixed-point.

- Is it indeed "the" fixed-point"?
- If not, in what sense a chosen fixed-point is canonical?

Thank you,
Jeehoon

2016-08-20 23:02 GMT+09:00 Jeehoon Kang <jeehoon.kang at sf.snu.ac.kr>:

> I think I almost understand pre-wp ;-)  But I still cannot understand
> the use of step-index: may I ask what is the intuition behind requiring
> m+1 \in ... for the value case?  I think I understand why you required m
> in ... in the reduction case, since there is actually a step.  But for the
> value case, I am not sure why it is necessary to demand m+1 \in ....  Why
> m \in ... is not enough?
>
> Thank you,
> Jeehoon
>
> 2016-08-19 21:14 GMT+09:00 Ralf Jung <jung at mpi-sws.org>:
>
>> Hi,
>>
>> > But I am still confused of the definition of pre-wp..  In the 2nd
>> > line, s should have the type ∆(Val), mandated by ϕ(s); and yet at
>> > the same time s should have the type Res, from s · rf.  May I ask if
>> > what am I missing here?
>>
>> Right, that should have been ϕ(v)(s). Then things hopefully make sense...
>>
>> Kind regards,
>> Ralf
>>
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>
>
>
> --
> Jeehoon Kang (Ph.D. student) <http://sf.snu.ac.kr/jeehoon.kang>
> Software Foundations Laboratory <http://sf.snu.ac.kr>
> Seoul National University <http://www.snu.ac.kr>
>

--
Jeehoon Kang (Ph.D. student) <http://sf.snu.ac.kr/jeehoon.kang>
Software Foundations Laboratory <http://sf.snu.ac.kr>
Seoul National University <http://www.snu.ac.kr>
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