## List of first-order theories |

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, a first-order theory is given by amathematical logic of axioms in some language. this entry lists some of the more common examples used inset and some of their properties.model theory - preliminaries
- pure identity theories
- unary relations
- equivalence relations
- orders
- lattices
- graphs
- boolean algebras
- groups
- rings and fields
- geometry
- differential algebra
- addition
- arithmetic
- second order arithmetic
- set theories
- see also
- references
- further reading

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