A microfluidics chip enables researchers to manipulate and study individual cells, without the use of agar at all. Credit: Brouzes E. et al. PNAS (2009).
I learned that for 4-SAT, if clause to variable ratio is more than 10, the generated problems become difficult to solve, and the likelihood of formula to be SAT or UNSAT is close to 50%. So I generated 3 types of formulas:
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Израиль нанес удар по Ирану09:28
除夕当晚，我们去了四川德阳灯会，现场还有歌舞和打铁花表演。南方周末记者 黄思卓/摄