2
votes
1answer
232 views
Since an inconsistent system can prove its own consistency…
Say a proof for the consistency of a formal system (proved within the formal system) is known. There are two possible cases: 1. the formal system is consistent and it can be and ha …
0
votes
1answer
160 views
How to prove a quadratic equation has at most two roots in first order theory of field [closed]
Consider the first order theory of fields, whose language contains constant symbol $0$ for additive identity, constant symbol $1$ for multiplicative identity, function symbol $A(x, …
0
votes
0answers
57 views
Optimal instance of quadratically constrained program
Consider the following optimization problem. Let $n, m \in \mathbb N$ and $0 < p_1 \leq \ldots \leq p_n ~ (p_i \in \mathbb R)$ be constant. The feasible region is described by a …
15
votes
3answers
740 views
Finite versions of Godel' s incompleteness
Assume you have some notion of proof complexity: for instance, at the basic level, the length of a proof, or the number of symbols used, take your pick (there are more involved mea …
2
votes
1answer
208 views
Sequent calculus: is there a complete linear reasoning (i.e., no trees)?
In Gentzen's sequent calculus, a formal proof is described by a tree, with each node representing the sequent obtained from the child(ren) by applying a given inference rule.
If n …
0
votes
0answers
224 views
Introduction to proofs: what is the best technique to use? [closed]
I just received my first assignment for a mathematical proofs course I am taking this year. We just began the course, and we have so far only covered examples of proofs (how to pro …
13
votes
4answers
2k views
How true are theorems proved by Coq?
Less tongue in cheek, is it known what the relative consistency is for theorems proved with an automatic theorem prover? Of course this depends somewhat on what assumptions one mak …
1
vote
0answers
292 views
Can someone help me in a proof about Kolakoski sequence? [closed]
Hello everyone.
I am not a mathematician but recently I was thinking about one of Kimberling's questions he posted here: http://faculty.evansville.edu/ck6/integer/index.html , i.e …
-2
votes
2answers
2k views
How to prove a limit exists using the epsilon delta definition of a limit [closed]
I understand how to find a limit. I understand the concept of the epsilon delta definition of a limit. Can you walk me through what we're doing in this worked example? It is fro …
10
votes
2answers
1k views
Consequences of technically proving anything in Coq (on at least Linux) exploiting a bug? [closed]
Technically, it is possible to prove anything in Coq proof assistant [1] (on at least Linux) due to a programming feature (or bug). This seems tractable when validating large proof …
8
votes
1answer
357 views
Proving that a combinatorial sequence has no compact formula
Suppose we have a sequence $a_n$ given by some combinatorial formula, e.g. involving a sum of n terms (like ${n \choose k}^{10}3^{-k}$ etc.). Sometimes it is plausible that there …
-2
votes
0answers
202 views
Proof using only symbolic logic [closed]
I really need an example of some non-trivial proof (not related directly to set theory) that uses only logical symbols (no "words").
Thanks.

