Godel 10

An important consequence of the completeness theorem is that it is possible to enumerate the logical consequences of any effective first-order theory, by enumerating all the correct deductions using axioms from the theory.

Gödel’s incompleteness theorem, referring to a different meaning of completeness, shows that if any sufficiently strong effective theory of arithmetic is consistent[,] then there is a formula (depending on the theory) which can neither be proven nor disproven within the theory. Nevertheless the completeness theorem applies to these theories, showing that any logical consequence of such a theory is provable from the theory.

— 14 February 2012

— Wikipedia on Gödel’s completeness theorem

2013.07.19 Friday ACHK

Free Software 5

自由軟體 5 | Consultant 2

Paying represents a recognition of value. Paying is a declaration of commitment.

Without enough payment, people in general will not commit enough time to fully utilize a product. 

— Me@2011.03.17

Free software is a matter of liberty, not price. To understand the concept, you should think of free as in free speech, not as in free beer.

— Richard Stallman

Free software does not have to be free. Free software does not have to be cheap.

Free Software Foundation sold each Emacs copy for 100 dollars.

— based on my memory of a Richard Stallman’s speech in Hong Kong

[The “$100” may be incorrect. But spirit of the whole paragraph is intact.]

— Me@2013.07.17

2013.07.19 Friday (c) All rights reserved by ACHK