Knowledge (XXG)

Strongly compact cardinal

Source 📝

22: 272: 143:. Given that the relevant cardinals exist, it is consistent with ZFC either that the first measurable cardinal is strongly compact, or that the first strongly compact cardinal is supercompact; these cannot both be true, however. A measurable limit of strongly compact cardinals is strongly compact, but the least such limit is not supercompact. 150:. Some set theorists conjecture that existence of a strongly compact cardinal is equiconsistent with that of a supercompact cardinal. However, a proof is unlikely until a canonical inner model theory for supercompact cardinals is developed. 127:
The property of strong compactness may be weakened by only requiring this compactness property to hold when the original collection of statements has cardinality below a certain cardinal λ; we may then refer to λ-compactness. A cardinal κ is
124:
property of finitary logic. Specifically, a statement which follows from some other collection of statements should also follow from some subcollection having cardinality less than κ.
51: 120:κ is defined by requiring the number of operands for each operator to be less than κ; then κ is strongly compact if its logic satisfies an analog of the 313: 252: 172: 73: 105:
An uncountable cardinal κ is strongly compact if and only if every κ-complete filter can be extended to a κ-complete ultrafilter.
201: 306: 34: 44: 38: 30: 337: 55: 332: 299: 129: 245:
Set Theory: An Introduction to Large Cardinals (Studies in Logic and the Foundations of Mathematics; V. 76)
140: 160: 136: 121: 210: 248: 283: 220: 117: 113: 109: 147: 99: 326: 154: 132:
if and only if it is κ-compact; this was the original definition of that concept.
193: 157:
which holds for an inaccessible cardinal if and only if it is strongly compact.
91: 279: 224: 87: 146:
The consistency strength of strong compactness is strictly above that of a
271: 215: 108:
Strongly compact cardinals were originally defined in terms of
15: 116:
are allowed to take infinitely many operands. The logic on a
194:"The super tree property at the successor of a singular" 287: 163:is a second-order analog of strong compactness. 43:but its sources remain unclear because it lacks 307: 8: 192:Hachtman, Sherwood; Sinapova, Dima (2020). 314: 300: 214: 74:Learn how and when to remove this message 184: 7: 268: 266: 286:. You can help Knowledge (XXG) by 14: 173:List of large cardinal properties 270: 20: 153:Jech obtained a variant of the 1: 202:Israel Journal of Mathematics 135:Strong compactness implies 354: 265: 225:10.1007/s11856-020-2000-5 96:strongly compact cardinal 247:. Elsevier Science Ltd. 29:This article includes a 58:more precise citations. 282:-related article is a 243:Drake, F. R. (1974). 98:is a certain kind of 139:, and is implied by 31:list of references 295: 294: 114:logical operators 84: 83: 76: 345: 338:Set theory stubs 316: 309: 302: 274: 267: 258: 229: 228: 218: 198: 189: 141:supercompactness 118:regular cardinal 110:infinitary logic 79: 72: 68: 65: 59: 54:this article by 45:inline citations 24: 23: 16: 353: 352: 348: 347: 346: 344: 343: 342: 333:Large cardinals 323: 322: 321: 320: 263: 261: 255: 242: 238: 233: 232: 196: 191: 190: 186: 181: 169: 148:Woodin cardinal 80: 69: 63: 60: 49: 35:related reading 25: 21: 12: 11: 5: 351: 349: 341: 340: 335: 325: 324: 319: 318: 311: 304: 296: 293: 292: 275: 260: 259: 253: 239: 237: 234: 231: 230: 209:(1): 473–500. 183: 182: 180: 177: 176: 175: 168: 165: 130:weakly compact 100:large cardinal 90:, a branch of 82: 81: 64:September 2023 39:external links 28: 26: 19: 13: 10: 9: 6: 4: 3: 2: 350: 339: 336: 334: 331: 330: 328: 317: 312: 310: 305: 303: 298: 297: 291: 289: 285: 281: 276: 273: 269: 264: 256: 254:0-444-10535-2 250: 246: 241: 240: 235: 226: 222: 217: 212: 208: 204: 203: 195: 188: 185: 178: 174: 171: 170: 166: 164: 162: 161:Extendibility 158: 156: 155:tree property 151: 149: 144: 142: 138: 137:measurability 133: 131: 125: 123: 119: 115: 111: 106: 103: 101: 97: 93: 89: 78: 75: 67: 57: 53: 47: 46: 40: 36: 32: 27: 18: 17: 288:expanding it 277: 262: 244: 206: 200: 187: 159: 152: 145: 134: 126: 107: 104: 95: 85: 70: 61: 50:Please help 42: 122:compactness 92:mathematics 56:introducing 327:Categories 280:set theory 236:References 216:1806.00820 88:set theory 179:Footnotes 167:See also 112:, where 52:improve 251:  278:This 211:arXiv 197:(PDF) 37:, or 284:stub 249:ISBN 94:, a 221:doi 207:236 86:In 329:: 219:. 205:. 199:. 102:. 41:, 33:, 315:e 308:t 301:v 290:. 257:. 227:. 223:: 213:: 77:) 71:( 66:) 62:( 48:.

Index

list of references
related reading
external links
inline citations
improve
introducing
Learn how and when to remove this message
set theory
mathematics
large cardinal
infinitary logic
logical operators
regular cardinal
compactness
weakly compact
measurability
supercompactness
Woodin cardinal
tree property
Extendibility
List of large cardinal properties
"The super tree property at the successor of a singular"
Israel Journal of Mathematics
arXiv
1806.00820
doi
10.1007/s11856-020-2000-5
ISBN
0-444-10535-2
Stub icon

Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.