La Classification Mathématique par matières 2000 Mathematics subject Classification 2000 Query : CC = 11U10 03-XX Mathematical logic and foundations 03H15 Nonstandard models of arithmetic [See also 11U10, 12L15, 13L05] 11-XX Number theory 11U10 Nonstandard arithmetic [See also 03H15] Keyword : Back to the Mathematics Subject Classification (version 2000)