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System F

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1696: 3006: 1318: 2698: 1691:{\displaystyle {\begin{aligned}\mathrm {AND} &=\lambda x^{\mathsf {Boolean}}\lambda y^{\mathsf {Boolean}}{.}x\,{\mathsf {Boolean}}\,y\,\mathbf {F} \\\mathrm {OR} &=\lambda x^{\mathsf {Boolean}}\lambda y^{\mathsf {Boolean}}{.}x\,{\mathsf {Boolean}}\,\mathbf {T} \,y\\\mathrm {NOT} &=\lambda x^{\mathsf {Boolean}}{.}x\,{\mathsf {Boolean}}\,\mathbf {F} \,\mathbf {T} \end{aligned}}} 3001:{\displaystyle {\begin{aligned}0&:=\Lambda \alpha .\lambda x^{\alpha }.\lambda f^{\alpha \to \alpha }.x\\1&:=\Lambda \alpha .\lambda x^{\alpha }.\lambda f^{\alpha \to \alpha }.fx\\2&:=\Lambda \alpha .\lambda x^{\alpha }.\lambda f^{\alpha \to \alpha }.f(fx)\\3&:=\Lambda \alpha .\lambda x^{\alpha }.\lambda f^{\alpha \to \alpha }.f(f(fx))\end{aligned}}} 2268: 2527: 530: 2097: 2630: 2007: 433: 3065: 1310: 179: 2394: 1006: 935: 440: 2686: 2263:{\displaystyle \mathrm {ISZERO} =\lambda n^{\forall \alpha .(\alpha \rightarrow \alpha )\rightarrow \alpha \rightarrow \alpha }{.}n\,{\mathsf {Boolean}}\,(\lambda x^{\mathsf {Boolean}}{.}\mathbf {F} )\,\mathbf {T} } 2343: 3169:: that every term in F2 satisfies a logical relation, which can be embedded into the logical relations P2. Reynolds proved that a Girard projection followed by a Reynolds embedding form the identity, i.e., the 2542: 3461: 1137: 1054: 721: 1877: 3165:: that in second-order intuitionistic predicate logic (P2), functions from the natural numbers to the natural numbers that can be proved total, form a projection from P2 into F2. Reynolds proved the 2703: 2547: 1323: 346: 4029: 1015:— not two — arguments. The latter two should be lambda expressions, but the first one should be a type. This fact is reflected in the fact that the type of these expressions is 1187:); otherwise, if such functions could be named (within System F), then there would be no need for the lambda-expressive apparatus capable of defining functions anonymously and for the 610: 2056: 1869: 1823: 1741: 1096: 787: 680: 3295: 789:
is the type of all functions which take as input a type α and two expressions of type α, and produce as output an expression of type α (note that we consider
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family. Over time, as the restrictions of HM-style type systems have become apparent, languages have steadily moved to more expressive logics for their type systems.
741: 630: 582: 290: 266: 202: 3267: 2522:{\displaystyle \forall \alpha .(K_{1}^{1}\rightarrow \dots \rightarrow \alpha )\dots \rightarrow (K_{1}^{m}\rightarrow \dots \rightarrow \alpha )\rightarrow \alpha } 115: 3245: 2378: 807: 1781: 1761: 941: 870: 3933:(1971). "Une Extension de l'Interpretation de Gödel à l'Analyse, et son Application à l'Élimination des Coupures dans l'Analyse et la Théorie des Types". 525:{\displaystyle {\frac {\Gamma ,\alpha ~{\text{type}}\vdash M{\mathbin {:}}\sigma }{\Gamma \vdash \Lambda \alpha .M{\mathbin {:}}\forall \alpha .\sigma }}} 3967: 3099:
The version of System F used in this article is as an explicitly typed, or Church-style, calculus. The typing information contained in λ-terms makes
4121: 3754: 300: 2638: 3161:, the second-order polymorphic lambda calculus (F2) was discovered by Girard (1972) and independently by Reynolds (1974). Girard proved the 3991: 3905: 2625:{\displaystyle {\begin{aligned}{\mathit {zero}}&:\mathrm {N} \\{\mathit {succ}}&:\mathrm {N} \rightarrow \mathrm {N} \end{aligned}}} 2296: 1056:; the universal quantifier binding the α corresponds to the Λ binding the alpha in the lambda expression itself. Also, note that 3675: 3408: 4078: 4056: 4022: 2002:{\displaystyle \mathrm {IFTHENELSE} =\Lambda \alpha .\lambda x^{\mathsf {Boolean}}\lambda y^{\alpha }\lambda z^{\alpha }.x\alpha yz} 1101: 1018: 685: 3141:, a Haskell compiler, goes beyond HM (as of 2008) and uses System F extended with non-syntactic type equality; non-HM features in 3583: 3146: 3126: 3859: 3130: 69: 2279: 428:{\displaystyle {\frac {\Gamma \vdash M{\mathbin {:}}\forall \alpha .\sigma }{\Gamma \vdash M\tau {\mathbin {:}}\sigma }}} 308: 4001:
Wells, J. B. (1994). "Typability and type checking in the second-order lambda-calculus are equivalent and undecidable".
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Cardelli, Luca; Martini, Simone; Mitchell, John C.; Scedrov, Andre (1994). "An extension of system F with subtyping".
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However, in it was shown that the obvious rules of conversion for this system, called F by chance, were converging.
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is the system which allows functions from types to types where the argument (and result) may be of any order.
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The typing rules of System F are those of simply typed lambda calculus with the addition of the following:
3913: 1188: 3758: 2019: 1832: 1786: 1704: 1059: 750: 643: 101:, and binders for them. As an example, the fact that the identity function can have any type of the form 97:
has variables ranging over terms, and binders for them, System F additionally has variables ranging over
3084: 1184: 296: 49: 4072: 4116: 3158: 312: 65: 3274: 541: 3772: 3300: 3119: 3060:{\displaystyle \forall \alpha .(\alpha \rightarrow \alpha )\rightarrow \alpha \rightarrow \alpha } 2065: 1164: 1142: 841: 819: 3755:"The Church Project: Typability and type checking in {S}ystem {F} are equivalent and undecidable" 3378: 3214: 1305:{\displaystyle {\mathsf {Boolean}}\rightarrow {\mathsf {Boolean}}\rightarrow {\mathsf {Boolean}}} 84: 3339: 3104: 2278:
System F allows recursive constructions to be embedded in a natural manner, related to that in
174:{\displaystyle \vdash \Lambda \alpha .\lambda x^{\alpha }.x:\forall \alpha .\alpha \to \alpha } 4052: 4044: 4018: 3987: 3901: 3614: 3536: 3516: 3496: 1197: 810: 231: 211: 726: 615: 567: 275: 251: 187: 4010: 3963: 3955:
Interprétation fonctionnelle et élimination des coupures de l'arithmétique d'ordre supérieur
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for a Curry-style variant of System F, that is, one that lacks explicit typing annotations.
3108: 87: 80: 3223: 2356: 3852: 3490: 3185: 2085: 861: 792: 320: 1001:{\displaystyle \mathbf {F} =\Lambda \alpha {.}\lambda x^{\alpha }\lambda y^{\alpha }{.}y} 930:{\displaystyle \mathbf {T} =\Lambda \alpha {.}\lambda x^{\alpha }\lambda y^{\alpha }{.}x} 3369:(the kind of functions from types to types, where the argument type is of a lower order) 632:
is bound. The first rule is that of application, and the second is that of abstraction.
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of the arguments for these mappings: they must be types rather than values. System F
3203: 3100: 744: 292:; the expression after the colon is the type of the lambda expression preceding it.) 205: 31: 3213:
can be defined inductively on a family of systems, where induction is based on the
3122:", or simply "HM", does have an easy type inference algorithm and is used for many 1139:, but it is not a symbol of System F itself, but rather a "meta-symbol". Likewise, 228:
is traditionally used to denote type-level functions, as opposed to the lower-case
4045:"V Polymorphism Ch. 23. Universal Types, Ch. 25. An ML Implementation of System F" 3645:
Girard, Jean-Yves (1986). "The system F of variable types, fifteen years later".
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are also "meta-symbols", convenient shorthands, of System F "assemblies" (in the
3625: 3188: 319:, together with even more expressive typed lambda calculi, including those with 316: 3107:(1994) settled an "embarrassing open problem" by proving that type checking is 17: 4014: 3679: 315:
that uses only universal quantification. System F can be seen as part of the
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For instance, the natural numbers can be defined as an inductive datatype
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in System F (without explicit type annotations) is undecidable. Under the
3796: 3731:"Typability and type checking in System F are equivalent and undecidable" 3620: 77: 2338:{\displaystyle K_{1}\rightarrow K_{2}\rightarrow \dots \rightarrow S} 3142: 1871:-typed terms as decision functions. However, if one is requested: 3680:"Practical Foundations for Programming Languages, Second Edition" 4004: 3456:{\displaystyle F_{\omega }={\underset {1\leq i}{\bigcup }}F_{i}} 3118:
for System F is impossible. A restriction of System F known as "
3617:— the existentially quantified counterparts of universal types 1214:-terms, we can define some logic operators (which are of type 3202:
combines the first axis (polymorphism) with the second axis (
1763:, specifying that the other two parameters that are given to 1132:{\displaystyle \forall \alpha .\alpha \to \alpha \to \alpha } 1049:{\displaystyle \forall \alpha .\alpha \to \alpha \to \alpha } 716:{\displaystyle \forall \alpha .\alpha \to \alpha \to \alpha } 2593: 2590: 2587: 2584: 2561: 2558: 2555: 2552: 248:
which is used for value-level functions. (The superscripted
2688:. The terms of this type comprise a typed version of the 3493:), though it does permit mappings from values to values ( 3481:
of the arguments in these mappings, it does restrict the
68:, thus forming a theoretical basis for languages such as 3570:, pronounced "F-sub", is an extension of system F with 311:, System F corresponds to the fragment of second-order 3980:
Girard, Jean-Yves; Lafont, Yves; Taylor, Paul (1989).
3935:
Proceedings of the Second Scandinavian Logic Symposium
3698:"Proofs of Programs and Formalisation of Mathematics" 3539: 3519: 3499: 3411: 3381: 3342: 3303: 3277: 3255: 3226: 3020: 2701: 2641: 2635:
The System F type corresponding to this structure is
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The following two definitions for the boolean values
795: 753: 729: 688: 646: 618: 590: 570: 544: 443: 349: 278: 254: 234: 214: 190: 118: 3860:Programming Languages and Foundations at Edinburgh 3545: 3525: 3505: 3455: 3394: 3361: 3328: 3289: 3261: 3239: 3059: 3011:If we reverse the order of the curried arguments ( 3000: 2680: 2624: 2521: 2384:of these constructors, you can define the type of 2372: 2337: 2262: 2076: 2050: 2001: 1863: 1825:. As in Church encodings, there is no need for an 1817: 1775: 1755: 1735: 1690: 1304: 1206: 1175: 1153: 1131: 1090: 1048: 1000: 929: 852: 830: 801: 781: 735: 715: 674: 624: 604: 576: 556: 524: 427: 284: 260: 240: 220: 196: 173: 109:would be formalized in System F as the judgement 3853:The Girard-Reynolds Isomorphism (second edition) 3533:abstraction), and mappings from types to types ( 3184:While System F corresponds to the first axis of 3091:, and returns another single-argument function. 2058:-typed value. The most fundamental predicate is 3773:"System FC: equality constraints and coercions" 3489:does not permit mappings from values to types ( 340: 3957:(Ph.D. thesis) (in French), UniversitĂ© Paris 7 4007:Symposium on Logic in Computer Science (LICS) 3513:abstraction), mappings from types to values ( 8: 30:For the electronic trance music artist, see 3875:. North Holland, Amsterdam. pp. 4–56. 3206:); it is a different, more complex system. 1011:(Note that the above two functions require 3880: 3746: 3538: 3518: 3498: 3447: 3425: 3416: 3410: 3386: 3380: 3353: 3341: 3314: 3302: 3276: 3254: 3231: 3225: 3019: 2955: 2939: 2879: 2863: 2812: 2796: 2748: 2732: 2702: 2700: 2640: 2613: 2605: 2583: 2582: 2573: 2551: 2550: 2546: 2544: 2487: 2475: 2470: 2431: 2419: 2414: 2396: 2364: 2358: 2317: 2304: 2298: 2255: 2254: 2246: 2241: 2216: 2215: 2204: 2180: 2179: 2178: 2170: 2131: 2101: 2099: 2069: 2067: 2024: 2023: 2021: 1978: 1965: 1933: 1932: 1881: 1879: 1837: 1836: 1834: 1791: 1790: 1788: 1768: 1748: 1709: 1708: 1706: 1679: 1678: 1673: 1672: 1648: 1647: 1646: 1638: 1613: 1612: 1587: 1579: 1574: 1573: 1549: 1548: 1547: 1539: 1514: 1513: 1481: 1480: 1458: 1449: 1448: 1444: 1420: 1419: 1418: 1410: 1385: 1384: 1352: 1351: 1326: 1322: 1320: 1278: 1277: 1250: 1249: 1222: 1221: 1219: 1199: 1168: 1166: 1146: 1144: 1103: 1064: 1063: 1061: 1020: 990: 984: 971: 959: 945: 943: 919: 913: 900: 888: 874: 872: 845: 843: 823: 821: 794: 755: 754: 752: 728: 687: 648: 647: 645: 617: 597: 589: 569: 543: 501: 500: 471: 470: 459: 444: 442: 411: 396: 395: 363: 362: 350: 348: 277: 253: 233: 213: 189: 138: 117: 4051:. MIT Press. pp. 339–362, 381–388. 3200:higher-order polymorphic lambda calculus 3083:. That is to say, a Church numeral is a 1191:, which works around that restriction.) 3637: 2353:itself appears within one of the types 3087:– it takes a single-argument function 2235: 2232: 2229: 2226: 2223: 2220: 2217: 2199: 2196: 2193: 2190: 2187: 2184: 2181: 2043: 2040: 2037: 2034: 2031: 2028: 2025: 1952: 1949: 1946: 1943: 1940: 1937: 1934: 1856: 1853: 1850: 1847: 1844: 1841: 1838: 1810: 1807: 1804: 1801: 1798: 1795: 1792: 1728: 1725: 1722: 1719: 1716: 1713: 1710: 1667: 1664: 1661: 1658: 1655: 1652: 1649: 1632: 1629: 1626: 1623: 1620: 1617: 1614: 1568: 1565: 1562: 1559: 1556: 1553: 1550: 1533: 1530: 1527: 1524: 1521: 1518: 1515: 1500: 1497: 1494: 1491: 1488: 1485: 1482: 1439: 1436: 1433: 1430: 1427: 1424: 1421: 1404: 1401: 1398: 1395: 1392: 1389: 1386: 1371: 1368: 1365: 1362: 1359: 1356: 1353: 1297: 1294: 1291: 1288: 1285: 1282: 1279: 1269: 1266: 1263: 1260: 1257: 1254: 1251: 1241: 1238: 1235: 1232: 1229: 1226: 1223: 1083: 1080: 1077: 1074: 1071: 1068: 1065: 860:are used, extending the definition of 774: 771: 768: 765: 762: 759: 756: 667: 664: 661: 658: 655: 652: 649: 3844: 3842: 3840: 3838: 3598:subtyping, which can be expressed in 605:{\displaystyle \alpha ~{\text{type}}} 76:. It was discovered independently by 7: 3582:since the 1980s because the core of 3553:abstraction at the level of types). 3071:is a function that takes a function 1701:Note that in the definitions above, 4083:: the workhorse of modern compilers 3873:Information and Computation, vol. 9 3757:. 29 September 2007. Archived from 3375:In the limit, we can define system 2084:if and only if its argument is the 2051:{\displaystyle {\mathsf {Boolean}}} 1864:{\displaystyle {\mathsf {Boolean}}} 1818:{\displaystyle {\mathsf {Boolean}}} 1736:{\displaystyle {\mathsf {Boolean}}} 1091:{\displaystyle {\mathsf {Boolean}}} 782:{\displaystyle {\mathsf {Boolean}}} 675:{\displaystyle {\mathsf {Boolean}}} 3969:Towards a Theory of Type Structure 3578:has been of central importance to 3520: 3021: 2923: 2847: 2780: 2716: 2642: 2614: 2606: 2574: 2398: 2132: 2117: 2114: 2111: 2108: 2105: 2102: 1916: 1909: 1906: 1903: 1900: 1897: 1894: 1891: 1888: 1885: 1882: 1594: 1591: 1588: 1462: 1459: 1333: 1330: 1327: 1105: 1022: 953: 882: 689: 507: 488: 482: 447: 383: 369: 353: 215: 153: 122: 25: 3696:Geuvers H, Nordström B, Dowek G. 1829:function as one can just use raw 3716:"Joe Wells's Research Interests" 3584:functional programming languages 3127:functional programming languages 2290:. These are functions typed as: 2256: 2247: 2070: 1680: 1674: 1575: 1450: 1169: 1147: 946: 875: 846: 824: 326:According to Girard, the "F" in 60:over types. System F formalizes 4122:Polymorphism (computer science) 4049:Types and Programming Languages 3898:Types and Programming Languages 3153:The Girard-Reynolds Isomorphism 3067:), then the Church numeral for 2349:Recursivity is manifested when 4003:Proceedings of the 9th Annual 3986:. Cambridge University Press. 3477:places no restrictions on the 3290:{\displaystyle J\Rightarrow K} 3281: 3051: 3045: 3042: 3036: 3030: 2991: 2988: 2979: 2973: 2959: 2906: 2897: 2883: 2816: 2752: 2692:, the first few of which are: 2672: 2669: 2663: 2657: 2654: 2610: 2513: 2510: 2504: 2498: 2495: 2481: 2463: 2460: 2454: 2448: 2442: 2439: 2425: 2407: 2329: 2323: 2310: 2251: 2205: 2162: 2156: 2153: 2147: 2141: 2016:is a function which returns a 1274: 1246: 1123: 1117: 1098:is a convenient shorthand for 1040: 1034: 796: 707: 701: 612:in the context indicates that 419: 405: 165: 1: 3943:10.1016/S0049-237X(08)70843-7 3937:. Amsterdam. pp. 63–92. 3822:"OCaml 4.09 reference manual" 3748:10.1016/S0168-0072(98)00047-5 557:{\displaystyle \sigma ,\tau } 3797:"OCaml 4.00.1 release notes" 3659:10.1016/0304-3975(86)90044-7 3647:Theoretical Computer Science 3329:{\displaystyle J\in F_{n-1}} 3114:Wells's result implies that 3095:Use in programming languages 3075:as argument and returns the 2077:{\displaystyle \mathbf {T} } 1176:{\displaystyle \mathbf {F} } 1154:{\displaystyle \mathbf {T} } 853:{\displaystyle \mathbf {F} } 831:{\displaystyle \mathbf {T} } 437: 343: 95:simply typed lambda calculus 54:simply typed lambda calculus 46:second-order lambda calculus 3580:programming language theory 3395:{\displaystyle F_{\omega }} 3171:Girard-Reynolds Isomorphism 42:polymorphic lambda calculus 4143: 3714:Wells, J.B. (2005-01-20). 3362:{\displaystyle K\in F_{n}} 3217:permitted in each system: 29: 4043:Pierce, Benjamin (2002). 3896:Pierce, Benjamin (2002). 3718:. Heriot-Watt University. 4015:10.1109/LICS.1994.316068 3546:{\displaystyle \lambda } 3526:{\displaystyle \Lambda } 3506:{\displaystyle \lambda } 2280:Martin-Löf's type theory 1207:{\displaystyle \lambda } 584:is a type variable, and 309:Curry–Howard isomorphism 241:{\displaystyle \lambda } 221:{\displaystyle \Lambda } 58:universal quantification 3856:University of Edinburgh 3592:parametric polymorphism 3269:(the kind of types) and 3145:'s type system include 2282:. Abstract structures ( 736:{\displaystyle \alpha } 625:{\displaystyle \alpha } 577:{\displaystyle \alpha } 285:{\displaystyle \alpha } 261:{\displaystyle \alpha } 197:{\displaystyle \alpha } 62:parametric polymorphism 3914:Bounded quantification 3882:10.1006/inco.1994.1013 3547: 3527: 3507: 3457: 3396: 3363: 3330: 3291: 3263: 3262:{\displaystyle \star } 3241: 3163:Representation Theorem 3061: 3002: 2682: 2626: 2523: 2374: 2339: 2264: 2078: 2052: 2003: 1865: 1819: 1777: 1757: 1743:is a type argument to 1737: 1692: 1306: 1208: 1189:fixed-point combinator 1177: 1155: 1133: 1092: 1050: 1002: 931: 854: 832: 803: 783: 737: 717: 676: 626: 606: 578: 558: 526: 429: 330:was picked by chance. 286: 262: 242: 222: 198: 175: 3761:on 29 September 2007. 3735:Ann. Pure Appl. Logic 3590:family, support both 3548: 3528: 3508: 3458: 3397: 3364: 3331: 3292: 3264: 3242: 3240:{\displaystyle F_{n}} 3085:higher-order function 3062: 3003: 2683: 2627: 2524: 2375: 2373:{\displaystyle K_{i}} 2340: 2265: 2079: 2053: 2004: 1866: 1820: 1778: 1758: 1738: 1693: 1307: 1209: 1194:Then, with these two 1178: 1156: 1134: 1093: 1051: 1003: 932: 855: 833: 804: 784: 738: 718: 677: 627: 607: 579: 559: 527: 430: 297:term rewriting system 287: 268:means that the bound 263: 243: 223: 199: 176: 66:programming languages 50:typed lambda calculus 27:Typed lambda calculus 4009:. pp. 176–185. 3729:Wells, J.B. (1999). 3586:, like those in the 3537: 3517: 3497: 3473:Note that although F 3409: 3379: 3340: 3301: 3275: 3253: 3224: 3159:intuitionistic logic 3018: 2699: 2639: 2543: 2395: 2357: 2297: 2286:) are created using 2098: 2066: 2020: 1878: 1833: 1787: 1767: 1747: 1705: 1319: 1218: 1198: 1165: 1143: 1102: 1060: 1019: 942: 871: 842: 820: 802:{\displaystyle \to } 793: 751: 727: 686: 682:type is defined as: 644: 636:Logic and predicates 616: 588: 568: 542: 441: 347: 313:intuitionistic logic 301:strongly normalizing 276: 252: 232: 212: 188: 116: 52:that introduces, to 4073:Summary of System F 3167:Abstraction Theorem 2480: 2424: 2274:System F structures 4030:Postscript version 3777:gitlab.haskell.org 3543: 3523: 3503: 3453: 3441: 3392: 3359: 3326: 3287: 3259: 3237: 3103:straightforward. 3057: 2998: 2996: 2678: 2622: 2620: 2536:with constructors 2519: 2466: 2410: 2370: 2335: 2260: 2074: 2048: 1999: 1861: 1815: 1773: 1753: 1733: 1688: 1686: 1302: 1204: 1173: 1151: 1129: 1088: 1046: 998: 927: 850: 828: 799: 779: 733: 713: 672: 622: 602: 574: 554: 522: 425: 282: 258: 238: 218: 208:. The upper-case 194: 171: 85:computer scientist 4107:1974 in computing 4102:1971 in computing 4075:by Franck Binard. 3993:978-0-521-37181-0 3951:Girard, Jean-Yves 3931:Girard, Jean-Yves 3907:978-0-262-16209-8 3685:. pp. 142–3. 3615:Existential types 3426: 1776:{\displaystyle x} 1756:{\displaystyle x} 811:right-associative 600: 596: 536: 535: 520: 462: 458: 423: 56:, a mechanism of 16:(Redirected from 4134: 4062: 4028: 3997: 3983:Proofs and Types 3976: 3974: 3958: 3946: 3916: 3911: 3893: 3887: 3886: 3884: 3868: 3862: 3846: 3833: 3832: 3830: 3829: 3818: 3812: 3811: 3809: 3808: 3793: 3787: 3786: 3784: 3783: 3769: 3763: 3762: 3752: 3750: 3741:(1–3): 111–156. 3726: 3720: 3719: 3711: 3705: 3704: 3702: 3693: 3687: 3686: 3684: 3672: 3666: 3665: 3642: 3552: 3550: 3549: 3544: 3532: 3530: 3529: 3524: 3512: 3510: 3509: 3504: 3462: 3460: 3459: 3454: 3452: 3451: 3442: 3440: 3421: 3420: 3401: 3399: 3398: 3393: 3391: 3390: 3368: 3366: 3365: 3360: 3358: 3357: 3335: 3333: 3332: 3327: 3325: 3324: 3296: 3294: 3293: 3288: 3268: 3266: 3265: 3260: 3246: 3244: 3243: 3238: 3236: 3235: 3157:In second-order 3124:statically typed 3090: 3082: 3078: 3074: 3070: 3066: 3064: 3063: 3058: 3007: 3005: 3004: 2999: 2997: 2966: 2965: 2944: 2943: 2890: 2889: 2868: 2867: 2823: 2822: 2801: 2800: 2759: 2758: 2737: 2736: 2687: 2685: 2684: 2679: 2631: 2629: 2628: 2623: 2621: 2617: 2609: 2597: 2596: 2577: 2565: 2564: 2535: 2528: 2526: 2525: 2520: 2491: 2479: 2474: 2435: 2423: 2418: 2387: 2383: 2379: 2377: 2376: 2371: 2369: 2368: 2352: 2344: 2342: 2341: 2336: 2322: 2321: 2309: 2308: 2285: 2269: 2267: 2266: 2261: 2259: 2250: 2245: 2240: 2239: 2238: 2203: 2202: 2174: 2169: 2168: 2120: 2090: 2083: 2081: 2080: 2075: 2073: 2061: 2057: 2055: 2054: 2049: 2047: 2046: 2008: 2006: 2005: 2000: 1983: 1982: 1970: 1969: 1957: 1956: 1955: 1912: 1870: 1868: 1867: 1862: 1860: 1859: 1828: 1824: 1822: 1821: 1816: 1814: 1813: 1782: 1780: 1779: 1774: 1762: 1760: 1759: 1754: 1742: 1740: 1739: 1734: 1732: 1731: 1697: 1695: 1694: 1689: 1687: 1683: 1677: 1671: 1670: 1642: 1637: 1636: 1635: 1597: 1578: 1572: 1571: 1543: 1538: 1537: 1536: 1505: 1504: 1503: 1465: 1453: 1443: 1442: 1414: 1409: 1408: 1407: 1376: 1375: 1374: 1336: 1311: 1309: 1308: 1303: 1301: 1300: 1273: 1272: 1245: 1244: 1213: 1211: 1210: 1205: 1182: 1180: 1179: 1174: 1172: 1160: 1158: 1157: 1152: 1150: 1138: 1136: 1135: 1130: 1097: 1095: 1094: 1089: 1087: 1086: 1055: 1053: 1052: 1047: 1007: 1005: 1004: 999: 994: 989: 988: 976: 975: 963: 949: 936: 934: 933: 928: 923: 918: 917: 905: 904: 892: 878: 859: 857: 856: 851: 849: 837: 835: 834: 829: 827: 808: 806: 805: 800: 788: 786: 785: 780: 778: 777: 742: 740: 739: 734: 722: 720: 719: 714: 681: 679: 678: 673: 671: 670: 631: 629: 628: 623: 611: 609: 608: 603: 601: 598: 594: 583: 581: 580: 575: 563: 561: 560: 555: 531: 529: 528: 523: 521: 519: 506: 505: 480: 476: 475: 463: 460: 456: 445: 434: 432: 431: 426: 424: 422: 415: 401: 400: 381: 368: 367: 351: 341: 291: 289: 288: 283: 267: 265: 264: 259: 247: 245: 244: 239: 227: 225: 224: 219: 203: 201: 200: 195: 180: 178: 177: 172: 143: 142: 88:John C. Reynolds 81:Jean-Yves Girard 21: 4142: 4141: 4137: 4136: 4135: 4133: 4132: 4131: 4112:Lambda calculus 4092: 4091: 4082: 4069: 4059: 4042: 4039: 4037:Further reading 4034: 4025: 4000: 3994: 3979: 3972: 3962: 3949: 3929: 3925: 3920: 3919: 3908: 3895: 3894: 3890: 3870: 3869: 3865: 3847: 3836: 3827: 3825: 3820: 3819: 3815: 3806: 3804: 3795: 3794: 3790: 3781: 3779: 3771: 3770: 3766: 3753: 3728: 3727: 3723: 3713: 3712: 3708: 3700: 3695: 3694: 3690: 3682: 3674: 3673: 3669: 3644: 3643: 3639: 3634: 3611: 3603: 3577: 3568: 3562: 3560: 3535: 3534: 3515: 3514: 3495: 3494: 3491:dependent types 3488: 3476: 3469: 3443: 3430: 3412: 3407: 3406: 3382: 3377: 3376: 3349: 3338: 3337: 3310: 3299: 3298: 3273: 3272: 3251: 3250: 3247:permits kinds: 3227: 3222: 3221: 3212: 3196: 3182: 3180: 3155: 3097: 3088: 3080: 3076: 3072: 3068: 3016: 3015: 2995: 2994: 2951: 2935: 2916: 2910: 2909: 2875: 2859: 2840: 2834: 2833: 2808: 2792: 2773: 2767: 2766: 2744: 2728: 2709: 2697: 2696: 2690:Church numerals 2637: 2636: 2619: 2618: 2598: 2579: 2578: 2566: 2541: 2540: 2533: 2393: 2392: 2385: 2381: 2360: 2355: 2354: 2350: 2313: 2300: 2295: 2294: 2283: 2276: 2211: 2127: 2096: 2095: 2088: 2064: 2063: 2059: 2018: 2017: 1974: 1961: 1928: 1876: 1875: 1831: 1830: 1826: 1785: 1784: 1765: 1764: 1745: 1744: 1703: 1702: 1685: 1684: 1608: 1598: 1584: 1583: 1509: 1476: 1466: 1455: 1454: 1380: 1347: 1337: 1317: 1316: 1216: 1215: 1196: 1195: 1163: 1162: 1141: 1140: 1100: 1099: 1058: 1057: 1017: 1016: 980: 967: 940: 939: 909: 896: 869: 868: 862:Church booleans 840: 839: 818: 817: 791: 790: 749: 748: 725: 724: 684: 683: 642: 641: 638: 614: 613: 586: 585: 566: 565: 540: 539: 481: 446: 439: 438: 382: 352: 345: 344: 336: 321:dependent types 274: 273: 250: 249: 230: 229: 210: 209: 186: 185: 134: 114: 113: 35: 28: 23: 22: 18:Universal types 15: 12: 11: 5: 4140: 4138: 4130: 4129: 4124: 4119: 4114: 4109: 4104: 4094: 4093: 4090: 4089: 4087:Greg Morrisett 4080: 4076: 4068: 4067:External links 4065: 4064: 4063: 4057: 4038: 4035: 4033: 4032: 4023: 3998: 3992: 3977: 3964:Reynolds, John 3960: 3947: 3926: 3924: 3921: 3918: 3917: 3912:, Chapter 26: 3906: 3888: 3863: 3834: 3813: 3788: 3764: 3721: 3706: 3688: 3667: 3636: 3635: 3633: 3630: 3629: 3628: 3623: 3618: 3610: 3607: 3601: 3575: 3566: 3561: 3558: 3555: 3542: 3522: 3502: 3486: 3474: 3467: 3464: 3463: 3450: 3446: 3439: 3436: 3433: 3429: 3424: 3419: 3415: 3389: 3385: 3373: 3372: 3371: 3370: 3356: 3352: 3348: 3345: 3323: 3320: 3317: 3313: 3309: 3306: 3286: 3283: 3280: 3270: 3258: 3234: 3230: 3210: 3204:type operators 3194: 3181: 3178: 3175: 3154: 3151: 3120:Hindley–Milner 3116:type inference 3096: 3093: 3056: 3053: 3050: 3047: 3044: 3041: 3038: 3035: 3032: 3029: 3026: 3023: 3009: 3008: 2993: 2990: 2987: 2984: 2981: 2978: 2975: 2972: 2969: 2964: 2961: 2958: 2954: 2950: 2947: 2942: 2938: 2934: 2931: 2928: 2925: 2922: 2919: 2917: 2915: 2912: 2911: 2908: 2905: 2902: 2899: 2896: 2893: 2888: 2885: 2882: 2878: 2874: 2871: 2866: 2862: 2858: 2855: 2852: 2849: 2846: 2843: 2841: 2839: 2836: 2835: 2832: 2829: 2826: 2821: 2818: 2815: 2811: 2807: 2804: 2799: 2795: 2791: 2788: 2785: 2782: 2779: 2776: 2774: 2772: 2769: 2768: 2765: 2762: 2757: 2754: 2751: 2747: 2743: 2740: 2735: 2731: 2727: 2724: 2721: 2718: 2715: 2712: 2710: 2708: 2705: 2704: 2677: 2674: 2671: 2668: 2665: 2662: 2659: 2656: 2653: 2650: 2647: 2644: 2633: 2632: 2616: 2612: 2608: 2604: 2601: 2599: 2595: 2592: 2589: 2586: 2581: 2580: 2576: 2572: 2569: 2567: 2563: 2560: 2557: 2554: 2549: 2548: 2530: 2529: 2518: 2515: 2512: 2509: 2506: 2503: 2500: 2497: 2494: 2490: 2486: 2483: 2478: 2473: 2469: 2465: 2462: 2459: 2456: 2453: 2450: 2447: 2444: 2441: 2438: 2434: 2430: 2427: 2422: 2417: 2413: 2409: 2406: 2403: 2400: 2380:. If you have 2367: 2363: 2347: 2346: 2334: 2331: 2328: 2325: 2320: 2316: 2312: 2307: 2303: 2275: 2272: 2271: 2270: 2258: 2253: 2249: 2244: 2237: 2234: 2231: 2228: 2225: 2222: 2219: 2214: 2210: 2207: 2201: 2198: 2195: 2192: 2189: 2186: 2183: 2177: 2173: 2167: 2164: 2161: 2158: 2155: 2152: 2149: 2146: 2143: 2140: 2137: 2134: 2130: 2126: 2123: 2119: 2116: 2113: 2110: 2107: 2104: 2086:Church numeral 2072: 2062:which returns 2045: 2042: 2039: 2036: 2033: 2030: 2027: 2010: 2009: 1998: 1995: 1992: 1989: 1986: 1981: 1977: 1973: 1968: 1964: 1960: 1954: 1951: 1948: 1945: 1942: 1939: 1936: 1931: 1927: 1924: 1921: 1918: 1915: 1911: 1908: 1905: 1902: 1899: 1896: 1893: 1890: 1887: 1884: 1858: 1855: 1852: 1849: 1846: 1843: 1840: 1812: 1809: 1806: 1803: 1800: 1797: 1794: 1772: 1752: 1730: 1727: 1724: 1721: 1718: 1715: 1712: 1699: 1698: 1682: 1676: 1669: 1666: 1663: 1660: 1657: 1654: 1651: 1645: 1641: 1634: 1631: 1628: 1625: 1622: 1619: 1616: 1611: 1607: 1604: 1601: 1599: 1596: 1593: 1590: 1586: 1585: 1582: 1577: 1570: 1567: 1564: 1561: 1558: 1555: 1552: 1546: 1542: 1535: 1532: 1529: 1526: 1523: 1520: 1517: 1512: 1508: 1502: 1499: 1496: 1493: 1490: 1487: 1484: 1479: 1475: 1472: 1469: 1467: 1464: 1461: 1457: 1456: 1452: 1447: 1441: 1438: 1435: 1432: 1429: 1426: 1423: 1417: 1413: 1406: 1403: 1400: 1397: 1394: 1391: 1388: 1383: 1379: 1373: 1370: 1367: 1364: 1361: 1358: 1355: 1350: 1346: 1343: 1340: 1338: 1335: 1332: 1329: 1325: 1324: 1299: 1296: 1293: 1290: 1287: 1284: 1281: 1276: 1271: 1268: 1265: 1262: 1259: 1256: 1253: 1248: 1243: 1240: 1237: 1234: 1231: 1228: 1225: 1203: 1185:Bourbaki sense 1171: 1149: 1128: 1125: 1122: 1119: 1116: 1113: 1110: 1107: 1085: 1082: 1079: 1076: 1073: 1070: 1067: 1045: 1042: 1039: 1036: 1033: 1030: 1027: 1024: 1009: 1008: 997: 993: 987: 983: 979: 974: 970: 966: 962: 958: 955: 952: 948: 937: 926: 922: 916: 912: 908: 903: 899: 895: 891: 887: 884: 881: 877: 848: 826: 798: 776: 773: 770: 767: 764: 761: 758: 747:. This means: 732: 712: 709: 706: 703: 700: 697: 694: 691: 669: 666: 663: 660: 657: 654: 651: 637: 634: 621: 593: 573: 553: 550: 547: 534: 533: 518: 515: 512: 509: 504: 499: 496: 493: 490: 487: 484: 479: 474: 469: 466: 455: 452: 449: 436: 421: 418: 414: 410: 407: 404: 399: 394: 391: 388: 385: 380: 377: 374: 371: 366: 361: 358: 355: 335: 332: 305:type inference 299:, System F is 281: 257: 237: 217: 193: 182: 181: 170: 167: 164: 161: 158: 155: 152: 149: 146: 141: 137: 133: 130: 127: 124: 121: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 4139: 4128: 4125: 4123: 4120: 4118: 4115: 4113: 4110: 4108: 4105: 4103: 4100: 4099: 4097: 4088: 4084: 4077: 4074: 4071: 4070: 4066: 4060: 4058:0-262-16209-1 4054: 4050: 4046: 4041: 4040: 4036: 4031: 4026: 4024:0-8186-6310-3 4020: 4016: 4012: 4008: 4006: 3999: 3995: 3989: 3985: 3984: 3978: 3971: 3970: 3965: 3961: 3956: 3952: 3948: 3944: 3940: 3936: 3932: 3928: 3927: 3922: 3915: 3909: 3903: 3900:. MIT Press. 3899: 3892: 3889: 3883: 3878: 3874: 3867: 3864: 3861: 3857: 3854: 3850: 3849:Philip Wadler 3845: 3843: 3841: 3839: 3835: 3823: 3817: 3814: 3802: 3798: 3792: 3789: 3778: 3774: 3768: 3765: 3760: 3756: 3749: 3744: 3740: 3736: 3732: 3725: 3722: 3717: 3710: 3707: 3703:. p. 51. 3699: 3692: 3689: 3681: 3677: 3671: 3668: 3664: 3660: 3656: 3652: 3648: 3641: 3638: 3631: 3627: 3624: 3622: 3619: 3616: 3613: 3612: 3608: 3606: 3604: 3597: 3593: 3589: 3585: 3581: 3573: 3569: 3556: 3554: 3540: 3500: 3492: 3484: 3480: 3471: 3448: 3444: 3437: 3434: 3431: 3427: 3422: 3417: 3413: 3405: 3404: 3403: 3387: 3383: 3354: 3350: 3346: 3343: 3321: 3318: 3315: 3311: 3307: 3304: 3284: 3278: 3271: 3256: 3249: 3248: 3232: 3228: 3220: 3219: 3218: 3216: 3207: 3205: 3201: 3197: 3190: 3187: 3176: 3174: 3172: 3168: 3164: 3160: 3152: 3150: 3148: 3144: 3140: 3136: 3132: 3128: 3125: 3121: 3117: 3112: 3110: 3106: 3102: 3101:type-checking 3094: 3092: 3086: 3054: 3048: 3039: 3033: 3027: 3024: 3014: 2985: 2982: 2976: 2970: 2967: 2962: 2956: 2952: 2948: 2945: 2940: 2936: 2932: 2929: 2926: 2920: 2918: 2913: 2903: 2900: 2894: 2891: 2886: 2880: 2876: 2872: 2869: 2864: 2860: 2856: 2853: 2850: 2844: 2842: 2837: 2830: 2827: 2824: 2819: 2813: 2809: 2805: 2802: 2797: 2793: 2789: 2786: 2783: 2777: 2775: 2770: 2763: 2760: 2755: 2749: 2745: 2741: 2738: 2733: 2729: 2725: 2722: 2719: 2713: 2711: 2706: 2695: 2694: 2693: 2691: 2675: 2666: 2660: 2651: 2648: 2645: 2602: 2600: 2570: 2568: 2539: 2538: 2537: 2516: 2507: 2501: 2492: 2488: 2484: 2476: 2471: 2467: 2457: 2451: 2445: 2436: 2432: 2428: 2420: 2415: 2411: 2404: 2401: 2391: 2390: 2389: 2365: 2361: 2332: 2326: 2318: 2314: 2305: 2301: 2293: 2292: 2291: 2289: 2281: 2273: 2242: 2212: 2208: 2175: 2171: 2165: 2159: 2150: 2144: 2138: 2135: 2128: 2124: 2121: 2094: 2093: 2092: 2087: 2015: 1996: 1993: 1990: 1987: 1984: 1979: 1975: 1971: 1966: 1962: 1958: 1929: 1925: 1922: 1919: 1913: 1874: 1873: 1872: 1770: 1750: 1643: 1639: 1609: 1605: 1602: 1600: 1580: 1544: 1540: 1510: 1506: 1477: 1473: 1470: 1468: 1445: 1415: 1411: 1381: 1377: 1348: 1344: 1341: 1339: 1315: 1314: 1313: 1201: 1192: 1190: 1186: 1126: 1120: 1114: 1111: 1108: 1043: 1037: 1031: 1028: 1025: 1014: 995: 991: 985: 981: 977: 972: 968: 964: 960: 956: 950: 938: 924: 920: 914: 910: 906: 901: 897: 893: 889: 885: 879: 867: 866: 865: 863: 814: 812: 746: 745:type variable 730: 710: 704: 698: 695: 692: 635: 633: 619: 591: 571: 551: 548: 545: 516: 513: 510: 502: 497: 494: 491: 485: 477: 472: 467: 464: 453: 450: 416: 412: 408: 402: 397: 392: 389: 386: 378: 375: 372: 364: 359: 356: 342: 339: 333: 331: 329: 324: 322: 318: 314: 310: 306: 302: 298: 293: 279: 271: 255: 235: 207: 206:type variable 191: 168: 162: 159: 156: 150: 147: 144: 139: 135: 131: 128: 125: 119: 112: 111: 110: 108: 104: 100: 96: 91: 89: 86: 82: 79: 75: 71: 67: 63: 59: 55: 51: 47: 43: 39: 33: 32:Ferry Corsten 19: 4048: 4002: 3982: 3968: 3954: 3934: 3897: 3891: 3872: 3866: 3826:. Retrieved 3824:. 2012-09-11 3816: 3805:. Retrieved 3803:. 2012-10-05 3800: 3791: 3780:. Retrieved 3776: 3767: 3759:the original 3738: 3734: 3724: 3709: 3691: 3670: 3662: 3650: 3646: 3640: 3599: 3564: 3563: 3482: 3478: 3472: 3465: 3374: 3208: 3199: 3192: 3186:Barendregt's 3183: 3170: 3166: 3162: 3156: 3113: 3098: 3012: 3010: 2634: 2531: 2348: 2288:constructors 2287: 2277: 2013: 2011: 1783:are of type 1700: 1193: 1012: 1010: 815: 639: 537: 337: 334:Typing rules 327: 325: 294: 269: 183: 106: 102: 98: 92: 45: 41: 37: 36: 4117:Type theory 3626:Lambda cube 3189:lambda cube 3109:undecidable 2012:will do. A 564:are types, 317:lambda cube 303:. However, 272:is of type 83:(1972) and 4096:Categories 3923:References 3828:2019-09-23 3807:2019-09-23 3782:2019-07-08 3574:. System F 3466:That is, F 3131:Haskell 98 1827:IFTHENELSE 3801:ocaml.org 3572:subtyping 3541:λ 3521:Λ 3501:λ 3435:≤ 3428:⋃ 3418:ω 3388:ω 3347:∈ 3319:− 3308:∈ 3282:⇒ 3257:⋆ 3105:Joe Wells 3079:power of 3055:α 3052:→ 3049:α 3046:→ 3040:α 3037:→ 3034:α 3025:α 3022:∀ 2963:α 2960:→ 2957:α 2949:λ 2941:α 2933:λ 2927:α 2924:Λ 2887:α 2884:→ 2881:α 2873:λ 2865:α 2857:λ 2851:α 2848:Λ 2820:α 2817:→ 2814:α 2806:λ 2798:α 2790:λ 2784:α 2781:Λ 2756:α 2753:→ 2750:α 2742:λ 2734:α 2726:λ 2720:α 2717:Λ 2676:α 2673:→ 2667:α 2664:→ 2661:α 2655:→ 2652:α 2646:α 2643:∀ 2611:→ 2517:α 2514:→ 2508:α 2505:→ 2502:⋯ 2499:→ 2485:α 2461:→ 2458:⋯ 2452:α 2449:→ 2446:⋯ 2443:→ 2429:α 2402:α 2399:∀ 2330:→ 2327:⋯ 2324:→ 2311:→ 2209:λ 2166:α 2163:→ 2160:α 2157:→ 2151:α 2148:→ 2145:α 2136:α 2133:∀ 2125:λ 2014:predicate 1991:α 1980:α 1972:λ 1967:α 1959:λ 1926:λ 1920:α 1917:Λ 1606:λ 1507:λ 1474:λ 1378:λ 1345:λ 1275:→ 1247:→ 1202:λ 1127:α 1124:→ 1121:α 1118:→ 1115:α 1109:α 1106:∀ 1044:α 1041:→ 1038:α 1035:→ 1032:α 1026:α 1023:∀ 986:α 978:λ 973:α 965:λ 957:α 954:Λ 915:α 907:λ 902:α 894:λ 886:α 883:Λ 797:→ 731:α 711:α 708:→ 705:α 702:→ 699:α 693:α 690:∀ 620:α 592:α 572:α 552:τ 546:σ 517:σ 511:α 508:∀ 492:α 489:Λ 486:⊢ 483:Γ 478:σ 465:⊢ 454:α 448:Γ 417:α 409:τ 403:σ 393:τ 387:⊢ 384:Γ 379:σ 373:α 370:∀ 357:⊢ 354:Γ 280:α 256:α 236:λ 216:Λ 192:α 169:α 166:→ 163:α 157:α 154:∀ 140:α 132:λ 126:α 123:Λ 120:⊢ 4079:System F 3966:(1974). 3953:(1972), 3676:Harper R 3621:System U 3609:See also 3600:System F 3565:System F 3557:System F 3483:universe 3209:System F 3193:System F 3177:System F 3133:and the 3129:such as 723:, where 328:System F 93:Whereas 78:logician 38:System F 3851:(2005) 3653:: 160. 3198:or the 70:Haskell 48:) is a 4081:ω 4055:  4021:  3990:  3904:  3596:record 3402:to be 3297:where 2060:ISZERO 809:to be 595:  538:where 457:  184:where 40:(also 4127:Logic 3973:(PDF) 3701:(PDF) 3683:(PDF) 3632:Notes 3602:<: 3576:<: 3567:<: 3559:<: 3479:order 3215:kinds 3143:OCaml 3013:i.e., 1013:three 743:is a 295:As a 204:is a 99:types 4053:ISBN 4019:ISBN 4005:IEEE 3988:ISBN 3902:ISBN 3594:and 3336:and 3147:GADT 2388:as: 1161:and 838:and 640:The 599:type 532:(2) 461:type 435:(1) 72:and 4085:by 4011:doi 3939:doi 3877:doi 3743:doi 3655:doi 3139:GHC 1312:): 813:.) 64:in 44:or 4098:: 4047:. 4017:. 3858:, 3837:^ 3799:. 3775:. 3739:98 3737:. 3733:. 3678:. 3661:. 3651:45 3649:. 3605:. 3588:ML 3191:, 3173:. 3149:. 3135:ML 2921::= 2845::= 2778::= 2714::= 2091:: 864:: 323:. 105:→ 90:. 74:ML 4061:. 4027:. 4013:: 3996:. 3975:. 3959:. 3945:. 3941:: 3910:. 3885:. 3879:: 3831:. 3810:. 3785:. 3751:. 3745:: 3657:: 3487:ω 3475:ω 3468:ω 3449:i 3445:F 3438:i 3432:1 3423:= 3414:F 3384:F 3355:n 3351:F 3344:K 3322:1 3316:n 3312:F 3305:J 3285:K 3279:J 3233:n 3229:F 3211:ω 3195:ω 3179:ω 3089:f 3081:f 3077:n 3073:f 3069:n 3043:) 3031:( 3028:. 2992:) 2989:) 2986:x 2983:f 2980:( 2977:f 2974:( 2971:f 2968:. 2953:f 2946:. 2937:x 2930:. 2914:3 2907:) 2904:x 2901:f 2898:( 2895:f 2892:. 2877:f 2870:. 2861:x 2854:. 2838:2 2831:x 2828:f 2825:. 2810:f 2803:. 2794:x 2787:. 2771:1 2764:x 2761:. 2746:f 2739:. 2730:x 2723:. 2707:0 2670:) 2658:( 2649:. 2615:N 2607:N 2603:: 2594:c 2591:c 2588:u 2585:s 2575:N 2571:: 2562:o 2559:r 2556:e 2553:z 2534:N 2511:) 2496:] 2493:S 2489:/ 2482:[ 2477:m 2472:1 2468:K 2464:( 2455:) 2440:] 2437:S 2433:/ 2426:[ 2421:1 2416:1 2412:K 2408:( 2405:. 2386:S 2382:m 2366:i 2362:K 2351:S 2345:. 2333:S 2319:2 2315:K 2306:1 2302:K 2284:S 2257:T 2252:) 2248:F 2243:. 2236:n 2233:a 2230:e 2227:l 2224:o 2221:o 2218:B 2213:x 2206:( 2200:n 2197:a 2194:e 2191:l 2188:o 2185:o 2182:B 2176:n 2172:. 2154:) 2142:( 2139:. 2129:n 2122:= 2118:O 2115:R 2112:E 2109:Z 2106:S 2103:I 2089:0 2071:T 2044:n 2041:a 2038:e 2035:l 2032:o 2029:o 2026:B 1997:z 1994:y 1988:x 1985:. 1976:z 1963:y 1953:n 1950:a 1947:e 1944:l 1941:o 1938:o 1935:B 1930:x 1923:. 1914:= 1910:E 1907:S 1904:L 1901:E 1898:N 1895:E 1892:H 1889:T 1886:F 1883:I 1857:n 1854:a 1851:e 1848:l 1845:o 1842:o 1839:B 1811:n 1808:a 1805:e 1802:l 1799:o 1796:o 1793:B 1771:x 1751:x 1729:n 1726:a 1723:e 1720:l 1717:o 1714:o 1711:B 1681:T 1675:F 1668:n 1665:a 1662:e 1659:l 1656:o 1653:o 1650:B 1644:x 1640:. 1633:n 1630:a 1627:e 1624:l 1621:o 1618:o 1615:B 1610:x 1603:= 1595:T 1592:O 1589:N 1581:y 1576:T 1569:n 1566:a 1563:e 1560:l 1557:o 1554:o 1551:B 1545:x 1541:. 1534:n 1531:a 1528:e 1525:l 1522:o 1519:o 1516:B 1511:y 1501:n 1498:a 1495:e 1492:l 1489:o 1486:o 1483:B 1478:x 1471:= 1463:R 1460:O 1451:F 1446:y 1440:n 1437:a 1434:e 1431:l 1428:o 1425:o 1422:B 1416:x 1412:. 1405:n 1402:a 1399:e 1396:l 1393:o 1390:o 1387:B 1382:y 1372:n 1369:a 1366:e 1363:l 1360:o 1357:o 1354:B 1349:x 1342:= 1334:D 1331:N 1328:A 1298:n 1295:a 1292:e 1289:l 1286:o 1283:o 1280:B 1270:n 1267:a 1264:e 1261:l 1258:o 1255:o 1252:B 1242:n 1239:a 1236:e 1233:l 1230:o 1227:o 1224:B 1170:F 1148:T 1112:. 1084:n 1081:a 1078:e 1075:l 1072:o 1069:o 1066:B 1029:. 996:y 992:. 982:y 969:x 961:. 951:= 947:F 925:x 921:. 911:y 898:x 890:. 880:= 876:T 847:F 825:T 775:n 772:a 769:e 766:l 763:o 760:o 757:B 696:. 668:n 665:a 662:e 659:l 656:o 653:o 650:B 549:, 514:. 503:: 498:M 495:. 473:: 468:M 451:, 420:] 413:/ 406:[ 398:: 390:M 376:. 365:: 360:M 270:x 160:. 151:: 148:x 145:. 136:x 129:. 107:A 103:A 34:. 20:)

Index

Universal types
Ferry Corsten
typed lambda calculus
simply typed lambda calculus
universal quantification
parametric polymorphism
programming languages
Haskell
ML
logician
Jean-Yves Girard
computer scientist
John C. Reynolds
simply typed lambda calculus
type variable
term rewriting system
strongly normalizing
type inference
Curry–Howard isomorphism
intuitionistic logic
lambda cube
dependent types
type variable
right-associative
Church booleans
Bourbaki sense
fixed-point combinator
Church numeral
Martin-Löf's type theory
Church numerals

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