Ultraproducts and elementary classes

Three uses of the Herbrand-Gentzen theorem in relating model theory and proof theory

William Craig · Journal of Symbolic Logic · 1957 · 672 citations

Humanities, Computer Science, Mathematics +13

The completeness of the first-order functional calculus

Leon Henkin · Journal of Symbolic Logic · 1949 · 537 citations

Humanities, Computer Science, Mathematics +9

Arithmetical extensions of relational systems

Alfred Tarski, Robert L. Vaught · French digital mathematics library (Numdam) · 1958 · 296 citations

Computing, Computer Science, Mathematics +14

Reduced direct products

T. Frayne, A. Morel, D. Scott · Fundamenta Mathematicae · 1962 · 238 citations · Full text

Universal relational systems

Bjàrni Jónsson · MATHEMATICA SCANDINAVICA · 1956 · 185 citations · Full text