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[urhegyi]

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....5.462.......1....2638.7..7..5...4.5.98.....842....6.1....8554....7..8.2...1..

[Hajime]

Hmm, if only I could prove that r1c3<>9 (backdoor) then stte except one xy-wing....

[P.O.]

basics:

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( n4r3c3   n5r9c4   n6r2c3   n8r4c9   n4r9c9   n4r4c8   n6r8c9
  n6r9c6 )

intersections:
((((7 0) (7 2 7) (3 7 9)) ((7 0) (9 2 7) (3 7 9)))
 (((3 0) (2 7 3) (3 5 9)) ((3 0) (2 9 3) (3 9)))
 (((1 0) (3 1 1) (1 9)) ((1 0) (3 2 1) (1 5 9))))


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9r4c127 => r1c46 r2c1 <> 7
 r4c1=9 - c1n2{r4 r2} - c1n7{r2 r1}
 r4c2=9 - r9n9{c2 c8} - b3n9{r3c8 r2c79} - 478r2c456
 r4c7=9 - c9n9{r6 r2} - 478r2c456
 
239r7c7 => r79c5 <> 3
 r7c7=2 - c8n2{r8 r5} - c8n7{r5 r6} - r6c6{n7 n1} - r4c5{n1 n3}
 r7c7=3 - r9c8{n3 n9} - r3n9{c8 c12} - r1c3{n9 n3} - r8n3{c3 c45}
 r7c7=9 - r9c8{n9 n3} - r9c5{n3 n7} - r7c4{n79 n3}
 
ste