Welcome to the Complexity Zoo... There are now 495 classes and counting!
This information was originally moved from http://www.complexityzoo.com/ in August 2005, and is currently under the watchful eyes of its original creators:
In 2012, this content was moved again to the University of Waterloo and is maintained there by
- Zoo Conservationist
- Vincent Russo
Errors? Omissions? Misattributions? Your favorite class not here? Then please contribute to the zoo as you see fit by signing up and clicking on the edit links. Please include references, or better yet links to papers if available.
To create a new class, click on the edit link of the class before or after the one that you want to add and copy the format of that class. (The classes are alphabetized by their tag names.) Then add the class to the table of contents and increment the total number of classes. After this, you can use the side edit links to edit the individual sections. For more on using the wiki language, see our simple wiki help page.
If you would like to contribute but feel unable to make the updates yourself, email the zookeeper at scott at scottaaronson.com.
- Introductory Essay: New visitors may want to stop here and see what the Zoo is all about.
- Petting Zoo: A more gentle version of the Zoo with fewer classes, meant for new initiates in complexity. (If you're looking for where the Most Important Classes went, look in the Petting Zoo.)
Other Collections and Resources
- Complexity Garden: Problems of interest in complexity theory and some notes about important inclusions.
- Special Exhibit: A collection of classes of quantum states and probability distributions.
- Complexity Zoology: A computer-assisted survey maintained by the Greg Kuperberg, including active and static inclusion diagrams.
- Complexity Zoo for iPad (and iPhone): An iOS viewer for Complexity Zoo.
- Glossary: Definitions of some complexity theoretic terms.
- References: Bibliography for the Zoo.
- Pronunciation Guide: A resource for those who insist on communicating verbally about complexity.
- Conventions and Notation: Common notational conventions used here at the Zoo.
- Operators: A (very short) list of operators which act upon classes.
- Acknowledgments: Where the Zookeeper and friends acknowledge those who have helped out with the Zoo.
- Complexity Zoo Contributor's Guide: A guide on how to get started helping out with the Zoo.
NB: Longtime Zoo watchers may recall Chris Bourke's LaTeX version of the Zoo and Chad Brewbaker's graphical inclusion diagram. These references are obsolete until further notice.
A0PP - AC - AC0 - AC0[m] - AC1 - ACC0 - AH - AL - ALL - ALOGTIME - AlgP/poly - Almost-NP - Almost-P - Almost-PSPACE - AM - AMEXP - AM ∩ coAM - AM[polylog] - AmpMP - AmpP-BQP - AP - APP - APX - ATIME - AUC-SPACE(f(n)) - AuxPDA - AVBPP - AvgE - AvgP - AW[P] - AWPP - AW[SAT] - AW[*] - AW[t] - AxP - AxPP
βP - BH - BPd(P) - BPE - BPEE - BPHSPACE(f(n)) - BPL - BPNP - BPP - BPPcc - BPPcc - BPPKT - BPP/log - BPP/mlog - BPP//log - BPP/rlog - BPP-OBDD - BPPpath - BPQP - BPSPACE(f(n)) - BPTIME(f(n)) - BQNC - BQNP - BQP - BQP/log - BQP/poly - BQP/mlog - BQP/mpoly - BQP/qlog - BQP/qpoly - BQP-OBDD - BQPSPACE - BQPCTC - BQPtt/poly - BQTIME(f(n)) - k-BWBP
C=AC0 - C=L - C=P - CC - CC0 - CFL - CLOG - CH - Check - CL#P - CkP - CNP - coAM - coC=P - cofrIP - Coh - coMA - coModkP - compIP - compNP - coNE - coNEXP - coNL - coNP - coNPcc - coNP/poly - coNQP - coRE - coRNC - coRP - coSL - coSPARSE - coUCC - coUP - CP - CSIZE(f(n)) - CSL - CSP - CZK
FBQP - Few - FewEXP - FewP - FH - FIXP - FNL - FNL/poly - FNP - FO - FO(DTC) - FO(LFP) - FO(PFP) - FO(TC) - FO() - FOLL - FP - FPNP[log] - FPR - FPRAS - FPT - FPTnu - FPTsu - FPTAS - FQMA - frIP - F-TAPE(f(n)) - F-TIME(f(n))
MA - MA' - MAC0 - MAE - MAEXP - mAL - MAPOLYLOG - MaxNP - MaxPB - MaxSNP - MaxSNP0 - mcoNL - MinPB - MIP - MIP*[2,1] - MIPEXP - (Mk)P - mL - MM - MMSNP - mNC1 - mNL - mNP - ModkL - ModL - ModkP - ModP - ModZkL - mP - MP - MPC - mP/poly - mTC0
NAuxPDAp - NC - NC0 - NC1 - NC2 - NE - NE/poly - Nearly-P - NEE - NEEE - NEEXP - NEXP - NEXP/poly - NIPZK - NIQSZK - NISZK - NISZKh - NL - NL/poly - NLIN - NLOG - NONE - NNC(f(n)) - NP - NPC - NPC - NPcc - NPcc - NPI - NP ∩ coNP - (NP ∩ coNP)/poly - NP/log - NPMV - NPMV-sel - NPMVt - NPMVt-sel - NPO - NPOPB - NP/poly - (NP,P-samplable) - NPR - NPSPACE - NPSV - NPSV-sel - NPSVt - NPSVt-sel - NQP - NSPACE(f(n)) - NT - NT* - NTIME(f(n))
P - P/log - P/poly - P#P - P#P - PCTC - PAC0 - PBP - k-PBP - PC - Pcc - Pcc - PCD(r(n),q(n)) - P-Close - PCP(r(n),q(n)) - PermUP - PEXP - PF - PFCHK(t(n)) - PH - PHcc - Φ2P - PhP - Π2P - PINC - PIO - PK - PKC - PL - PL1 - PL∞ - PLF - PLL - PLS - PNP - P||NP - PNP[k] - PNP[log] - PNP[log^2] - P-OBDD - PODN - polyL - PostBQP - PP - PPcc - PP/poly - PPA - PPAD - PPADS - PPP - PPP - PPSPACE - PQUERY - PR - PR - PrHSPACE(f(n)) - PromiseBPP - PromiseBQP - PromiseP - PromiseRP - PromiseUP - PrSPACE(f(n)) - P-Sel - PSK - PSPACE - PSPACE/poly - PT1 - PTAPE - PTAS - PT/WK(f(n),g(n)) - PZK
Q - QAC0 - QAC0[m] - QACC0 - QACf0 - QAM - QCFL - QCMA - QH - QIP - QIP - QL - QMA - QMA-plus - QMA(2) - QMA1 - QMAlog - QMAM - QMA/qpoly - QMIP - QMIPle - QMIPne - QNC - QNC0 - QNCf0 - QNC1 - QP - QPLIN - QPSPACE - QRG - QS2P - QSZK
S2P - S2-EXPPNP - SAC - SAC0 - SAC1 - SAPTIME - SBP - SBQP - SC - SE - SEH - SelfNP - SFk - Σ2P - SKC - SL - SLICEWISE PSPACE - SNP - SO - SO(Horn) - SO(Krom) - SO(LFP) - SO(TC) - SO - SP - span-P - SPARSE - SPL - SPP - SQG - SUBEXP - symP - SZK - SZKh