Jin-Yi Cai is Professor of Computer Science and the Steenbock Professor of Mathematical Sciences at the University of Wisconsin, Madison. He studied at Fudan University, Shanghai (class of 77) and at Cornell University, New York, receiving his Ph.D. in 1986. He held faculty positions at Yale University, Connecticut (1986–1989), Princeton University, New Jersey (1989–1993), and State University of New York, Buffalo (1993–2000), where he rose from Assistant Professor to Full Professor in 1996. He received a Presidential Young Investigator Award (1990), an Alfred P. Sloan Fellowship (1994), and a John Simon Guggenheim Fellowship (1998). He is a Fellow of the Association for Computing Machinery (ACM) and the American Association for the Advancement of Science (AAAS). Xi Chen is Associate Professor of Computer Science at Columbia University, New York. He studied at Tsinghua University and received his Ph.D. in 2007. His research focuses on complexity theory and algorithmic game theory. He is the recipient of a NSF CAREER Award, an Alfred P. Sloan Fellowship (2012), and an European Association for Theoretical Computer Science (EATCS) Presburger Award (2015).

• 1. Counting problems; 2. Fibonacci gates and Holant problems; 3. Boolean #CSP; 4. Matchgates and holographic algorithms; 5. 2-spin systems on regular graphs; 6. Holant problems and #CSP; 7. Holant dichotomy for symmetric constraints; 8. Planar #CSP for symmetric constraints; 9. Planar Holant for symmetric constraints; 10. Dichotomies for asymmetric constraints.

'This remarkable volume presents persuasive evidence that computer applications obey beautiful unities: within the significant classes considered, the problems that are not known to be polynomial time computable are all reducible to each other by a small number of elegant techniques. The treatment is original, comprehensive and thought provoking.' Leslie Valiant, Harvard University, Massachusetts

Jin-Yi Cai is Professor of Computer Science and the Steenbock Professor of Mathematical Sciences at the University of Wisconsin, Madison. He studied at Fudan University, Shanghai (class of 77) and at Cornell University, New York, receiving his Ph.D. in 1986. He held faculty positions at Yale University, Connecticut (1986–1989), Princeton University, New Jersey (1989–1993), and State University of New York, Buffalo (1993–2000), where he rose from Assistant Professor to Full Professor in 1996. He received a Presidential Young Investigator Award (1990), an Alfred P. Sloan Fellowship (1994), and a John Simon Guggenheim Fellowship (1998). He is a Fellow of the Association for Computing Machinery (ACM) and the American Association for the Advancement of Science (AAAS). Xi Chen is Associate Professor of Computer Science at Columbia University, New York. He studied at Tsinghua University and received his Ph.D. in 2007. His research focuses on complexity theory and algorithmic game theory. He is the recipient of a NSF CAREER Award, an Alfred P. Sloan Fellowship (2012), and an European Association for Theoretical Computer Science (EATCS) Presburger Award (2015).

• 1. Counting problems; 2. Fibonacci gates and Holant problems; 3. Boolean #CSP; 4. Matchgates and holographic algorithms; 5. 2-spin systems on regular graphs; 6. Holant problems and #CSP; 7. Holant dichotomy for symmetric constraints; 8. Planar #CSP for symmetric constraints; 9. Planar Holant for symmetric constraints; 10. Dichotomies for asymmetric constraints.

'This remarkable volume presents persuasive evidence that computer applications obey beautiful unities: within the significant classes considered, the problems that are not known to be polynomial time computable are all reducible to each other by a small number of elegant techniques. The treatment is original, comprehensive and thought provoking.' Leslie Valiant, Harvard University, Massachusetts

Jin-Yi Cai is Professor of Computer Science and the Steenbock Professor of Mathematical Sciences at the University of Wisconsin, Madison. He studied at Fudan University, Shanghai (class of 77) and at Cornell University, New York, receiving his Ph.D. in 1986. He held faculty positions at Yale University, Connecticut (1986–1989), Princeton University, New Jersey (1989–1993), and State University of New York, Buffalo (1993–2000), where he rose from Assistant Professor to Full Professor in 1996. He received a Presidential Young Investigator Award (1990), an Alfred P. Sloan Fellowship (1994), and a John Simon Guggenheim Fellowship (1998). He is a Fellow of the Association for Computing Machinery (ACM) and the American Association for the Advancement of Science (AAAS). Xi Chen is Associate Professor of Computer Science at Columbia University, New York. He studied at Tsinghua University and received his Ph.D. in 2007. His research focuses on complexity theory and algorithmic game theory. He is the recipient of a NSF CAREER Award, an Alfred P. Sloan Fellowship (2012), and an European Association for Theoretical Computer Science (EATCS) Presburger Award (2015).

• 1. Counting problems; 2. Fibonacci gates and Holant problems; 3. Boolean #CSP; 4. Matchgates and holographic algorithms; 5. 2-spin systems on regular graphs; 6. Holant problems and #CSP; 7. Holant dichotomy for symmetric constraints; 8. Planar #CSP for symmetric constraints; 9. Planar Holant for symmetric constraints; 10. Dichotomies for asymmetric constraints.

'This remarkable volume presents persuasive evidence that computer applications obey beautiful unities: within the significant classes considered, the problems that are not known to be polynomial time computable are all reducible to each other by a small number of elegant techniques. The treatment is original, comprehensive and thought provoking.' Leslie Valiant, Harvard University, Massachusetts