first_order_interpretation (581B)
1 # First order interpretation 2 3 A *d-dimensional FO interpretation* defines: 4 5 - an [FO] formula of arity d for domain elements, among d-tuples 6 - an [FO] formula of arity 2d, for equality 7 - we take the [quotient] under it 8 - [FO] formulas of arity dk to define [relations] of arity k 9 10 This allows [formulas] on the image of the FO interpretation to be "translated back" to the source of the FO interpretation 11 12 We can get rid of equality, cf [morvan2025homomorphism], Prop VII.3.2 13 14 Up: [logic_interpretation], [FO] 15 16 Aliases: FO interpretation, FO reduction 17 18 See also: [FO_projection]