Definition:Subsignature

Definition
Let $\LL, \LL'$ be signatures for the language of predicate logic.

Then $\LL$ is said to be a subsignature of $\LL'$''', denoted $\LL \subseteq \LL'$,, for each $n \in \N$:


 * $\map {\FF_n} \LL \subseteq \map {\FF_n} {\LL'}$
 * $\map {\PP_n} \LL \subseteq \map {\PP_n} {\LL'}$

where $\FF_n$ denotes the collection of $n$-ary function symbols, and $\PP_n$ denotes the collection of $n$-ary predicate symbols.

Also see

 * Definition:Signature for Predicate Logic


 * Definition:Expansion of Structure
 * Definition:Reduct of Structure