[jpt4]

The first order theories of the real numbers using addition and multiplication are decidable [0], while FO theories of the integers under the same operations are not.

[0] https://en.wikipedia.org/wiki/Decidability_of_first-order_th...

[vinnyvichy]

Wikipedia can be confusing..

https://mathoverflow.net/questions/134259/is-the-first-order...