11-XX - Number theory

11Uxx - Connections with logic

1	11U05	Decidability [See also 03B25]
	11U07	Ultraproducts [See also 03C20]
	11U09	Model theory [See also 03Cxx]
	11U10	Nonstandard arithmetic [See also 03H15]
	11U99	None of the above, but in this section