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Single Idea 13801

[filed under theme 5. Theory of Logic / H. Proof Systems / 1. Proof Systems ]

Full Idea

An 'informal proof' is not in any particular proof system. One may use any rule of proof that is 'sufficiently obvious', and there is quite a lot of ordinary English in the proof, explaining what is going on at each step.

Gist of Idea

An 'informal proof' is in no particular system, and uses obvious steps and some ordinary English

Source

David Bostock (Intermediate Logic [1997], 8.1)

Book Ref

Bostock,David: 'Intermediate Logic' [OUP 1997], p.327

The 4 ideas with the same theme [general ideas about the different proof systems]:

13824 Proof theory began with Frege's definition of derivability [Frege, by Prawitz]
15089 Logical proof just explicates complicated tautologies [Wittgenstein]
13801 An 'informal proof' is in no particular system, and uses obvious steps and some ordinary English [Bostock]
15406 'Induction' and 'recursion' on complexity prove by connecting a formula to its atomic components [Burgess]