[FOM] 167:Incompleteness Reformulated/More
Harvey Friedman
friedman at math.ohio-state.edu
Tue May 6 23:57:32 EDT 2003
In posting 165, I hadn't thought about T containing or deriving S.
Here is a sharper version of posting 165.
THEOREM 1. Let S be any consistent finite set of sentences in
predicate calculus. There exists a consistent finite set T of
sentences in predicate calculus such that T is not interpretable in
S. We can take T to include S.
THEOREM 2. Let S be any consistent recursively enumerable set of
sentences in predicate calculus, not mentioning the binary relation
symbol R. There exists a consistent finite set T of sentences in
predicate calculus with R only such that T is not interpretable in S.
THEOREM 3. Let S be any consistent recursively enumerable set of
sentences in predicate calculus, in a finite relational type. There
exists a consistent finite set T of sentences in predicate calculus
such that T is not interpretable in S. We can take T to prove S.
Here we take "interpretable" in the classical sense of Tarski.
Theorems 1,2,3 can be easily obtained from well known forms of the
Godel second incompleteness theorem.
Theorems 1,2,3 can instead be proved using well known recursion
theoretic ideas.
Note that there is no technical hypotheses appearing in these formulations.
The second incompleteness theorem gives a particularly interesting
construction of T from S.
THEOREM 4. There is a consistent finite set of sentences K in
predicate calculus such that any consistent recursively enumerable
set of sentences T in predicate calculus that interprets K is
incomplete.
The first incompleteness theorem gives a particularly interesting
construction of K.
We can ask: how tiny can K be?
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This is the 167th in a series of self contained postings to FOM covering
a wide range of topics in f.o.m. Previous ones counting from #100 are:
100:Boolean Relation Theory IV corrected 3/21/01 11:29AM
101:Turing Degrees/1 4/2/01 3:32AM
102: Turing Degrees/2 4/8/01 5:20PM
103:Hilbert's Program for Consistency Proofs/1 4/11/01 11:10AM
104:Turing Degrees/3 4/12/01 3:19PM
105:Turing Degrees/4 4/26/01 7:44PM
106.Degenerative Cloning 5/4/01 10:57AM
107:Automated Proof Checking 5/25/01 4:32AM
108:Finite Boolean Relation Theory 9/18/01 12:20PM
109:Natural Nonrecursive Sets 9/26/01 4:41PM
110:Communicating Minds I 12/19/01 1:27PM
111:Communicating Minds II 12/22/01 8:28AM
112:Communicating MInds III 12/23/01 8:11PM
113:Coloring Integers 12/31/01 12:42PM
114:Borel Functions on HC 1/1/02 1:38PM
115:Aspects of Coloring Integers 1/3/02 10:02PM
116:Communicating Minds IV 1/4/02 2:02AM
117:Discrepancy Theory 1/6/02 12:53AM
118:Discrepancy Theory/2 1/20/02 1:31PM
119:Discrepancy Theory/3 1/22.02 5:27PM
120:Discrepancy Theory/4 1/26/02 1:33PM
121:Discrepancy Theory/4-revised 1/31/02 11:34AM
122:Communicating Minds IV-revised 1/31/02 2:48PM
123:Divisibility 2/2/02 10:57PM
124:Disjoint Unions 2/18/02 7:51AM
125:Disjoint Unions/First Classifications 3/1/02 6:19AM
126:Correction 3/9/02 2:10AM
127:Combinatorial conditions/BRT 3/11/02 3:34AM
128:Finite BRT/Collapsing Triples 3/11/02 3:34AM
129:Finite BRT/Improvements 3/20/02 12:48AM
130:Finite BRT/More 3/21/02 4:32AM
131:Finite BRT/More/Correction 3/21/02 5:39PM
132: Finite BRT/cleaner 3/25/02 12:08AM
133:BRT/polynomials/affine maps 3/25/02 12:08AM
134:BRT/summation/polynomials 3/26/02 7:26PM
135:BRT/A Delta fA/A U. fA 3/27/02 5:45PM
136:BRT/A Delta fA/A U. fA/nicer 3/28/02 1:47AM
137:BRT/A Delta fA/A U. fA/beautification 3/28/02 4:30PM
138:BRT/A Delta fA/A U. fA/more beautification 3/28/02 5:35PM
139:BRT/A Delta fA/A U. fA/better 3/28/02 10:07PM
140:BRT/A Delta fA/A U. fA/yet better 3/29/02 10:12PM
141:BRT/A Delta fA/A U. fA/grammatical improvement 3/29/02 10:43PM
142:BRT/A Delta fA/A U. fA/progress 3/30/02 8:47PM
143:BRT/A Delta fA/A U. fA/major overhaul 5/2/02 2:22PM
144: BRT/A Delta fA/A U. fA/finesse 4/3/02 4:29AM
145:BRT/A U. B U. TB/simplification/new chapter 4/4/02 4:01AM
146:Large large cardinals 4/18/02 4:30AM
147:Another Way 7:21AM 4/22/02
148:Finite forms by relativization 2:55AM 5/15/02
149:Bad Typo 1:59PM 5/15/02
150:Finite obstruction/statisics 8:55AM 6/1/02
151:Finite forms by bounding 4:35AM 6/5/02
152:sin 10:35PM 6/8/02
153:Large cardinals as general algebra 1:21PM 6/17/02
154:Orderings on theories 5:28AM 6/25/02
155:A way out 8/13/02 6:56PM
156:Societies 8/13/02 6:56PM
157:Finite Societies 8/13/02 6:56PM
158:Sentential Reflection 3/31/03 12:17AM
159.Elemental Sentential Reflection 3/31/03 12:17AM
160.Similar Subclasses 3/31/03 12:17AM
161:Restrictions and Extensions 3/31/03 12:18AM
162:Two Quantifier Blocks 3/31/03 12:28PM
163:Ouch! 4/20/03 3:08AM
164:Foundations with (almost) no axioms, 4/22/0 5:31PM
165:Incomplelteness Reformulated 4/29/03 1:42PM
166:Clean Godel Incompleteness 5/6/03 11:06AM
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