A last esthetic suggestion: let's mark the lower group and label with 1 the last move Black did in the ko:
https://drive.google.com/file/d/1L62m7i_IJX8FCB_8rIOwjYK3tR1GZZaq/view?usp=sharing On 23 June 2018 at 00:19, Marcel Crasmaru <crasma...@gmail.com> wrote: > Well all my reasoning was good but for the formula which is actually > > F = z || (y && x) :-) > > Mea culpa I didn't see that the ladder choices are reversed. I let > other people try showing that the group is alive in John's initial > problem (last move was B capture at x, the lower side ko). > > --Marcel > > On 23 June 2018 at 00:06, Marcel Crasmaru <crasma...@gmail.com> wrote: >> OK I think there is one thing to be done to make the solution longer: >> >> 1. mark the middle ko and then >> 2. problem should be: B just captured in the middle ko and W is to >> move - is the group alive? >> >> See here: >> https://drive.google.com/file/d/1J5Xn4XkOqSsYx0AEBQJj6EL-SjNqNq-o/view?usp=sharing >> >> Assuming x is the top ko, y the middle one etc. the problem is then >> equivalent to >> F = z && (y || x) with (x = 1, y = 0, z = 0, F is false) and W cannot play >> at y. >> >> As F is false W has to take the ko at z (x = 1, y = 0, z = 1, F becomes true) >> B takes at x (x = 0, y = 0, z = 1 F is false) >> W takes at y (x = 0, y = 1, z = 1, F true), >> B takes at z (x = 0, y = 1, z = 0, F false) and W is dead as no matter >> what W does F remains false (equivalent to ladders failing for W). >> >> --Marcel >> >> On 22 June 2018 at 22:27, Marcel Crasmaru <crasma...@gmail.com> wrote: >>> Errata: assuming x is the top ko then the formula encoded by this problem is >>> >>> z && (y || x) >>> >>> with x = 1, y = 0, z = 0 and W cannot play at z. Thus W is already >>> dead you cannot make the formula true. >>> >>> --Marcel >>> >>> On 22 June 2018 at 22:19, Marcel Crasmaru <crasma...@gmail.com> wrote: >>>> The position looks OK is great - I didn't find any side solutions. >>>> Just one observation: I think this encodes x && y || y || z and W is >>>> dead already thus is arguably a easier problem :) >>>> >>>> Should make for a great wall poster. >>>> >>>> On 22 June 2018 at 19:48, John Tromp <john.tr...@gmail.com> wrote: >>>>>>>>> at the bottom of my Go page http://tromp.github.io/go.html, which also >>>>>>>>> contains an sgf link. >>>>>>>>> Direct link to image: http://tromp.github.io/img/WO5lives.png >>>>> >>>>> Enlarging the board to 29x29 allows for a much better final (I hope) >>>>> look, close to my first attempt. >>>>> >>>>> -John >>>>> _______________________________________________ >>>>> Computer-go mailing list >>>>> Computer-go@computer-go.org >>>>> http://computer-go.org/mailman/listinfo/computer-go _______________________________________________ Computer-go mailing list Computer-go@computer-go.org http://computer-go.org/mailman/listinfo/computer-go
