Satisfaction (original) (raw)

Algebra Applied Mathematics Calculus and Analysis Discrete Mathematics Foundations of Mathematics Geometry History and Terminology Number Theory Probability and Statistics Recreational Mathematics Topology

Alphabetical Index New in MathWorld


Let A be a relational system, and let L be a language which is appropriate for A. Let phi be a well-formed formula of L, and let s be a valuation in A. Then A|=_sphi is written provided that one of the following holds:

1. phi is of the form x=y, for some variables x and y of L, and s maps x and y to the same element of the structure A.

2. phi is of the form Rx_1...x_n, for some n-ary predicate symbol R of the language L, and some variables x_1,...,x_n of L, and {s(x_1),...,s(x_n)} is a member of R^A.

3. phi is of the form (psi ^ gamma), for some formulas psi and gamma of L such that A|=_spsi and A|=_sgamma.

4. phi is of the form (( exists  x)psi), and there is an element a of A such that A|=_(s(x|a))psi.

In this case, A is said to satisfy phi with the valuation s.


See also

Łoś' Theorem

This entry contributed by Matt Insall (author's link)

Explore with Wolfram|Alpha

References

Bell, J. L. and Slomson, A. B. Models and Ultraproducts: an Introduction. Amsterdam, Netherlands: North-Holland, 1969.Enderton, H. E. A Mathematical Introduction to Logic. Boston, MA: Academic Press, 1972.

Referenced on Wolfram|Alpha

Satisfaction

Cite this as:

Insall, Matt. "Satisfaction." From MathWorld--A Wolfram Web Resource, created by Eric W. Weisstein. https://mathworld.wolfram.com/Satisfaction.html

Subject classifications