Random reconstruction in two dimensions

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Bhargav Narayanan, Rutgers

Suppose that we only see small 鈥渒 x k snapshots鈥 of a random two-dimensional 鈥渘 x n picture鈥: can we piece the original picture back together? Motivated by the one-dimensional problem of shotgun sequencing DNA, Mossel and Ross raised several interesting questions (like the one aforementioned) about reconstructingrandom structures from 鈥渟mall snapshots鈥 in two (and higher) dimensions. In this talk, I will sketch how we can now answer some of these two-dimensional reconstruction questions: in particular, it turns out that the answer to the problem mentioned above exhibits somewhat surprising 鈥渢wo-point concentration,鈥 and getting to this answer involves a combination of entropic methods and tools from percolation.