Simon B. Resonances in one dimension and Fredholm determinants (53K, LaTeX) ABSTRACT. We discuss resonances for Schrodinger operators in whole- and half-line problems. One of our goals is to connect the Fredholm determinant approach of Froese to the Fourier transform approach of Zworski. Another is to prove a result on the number of antibound states --- namely, in a half-line problem there are an odd number of antibound states between any two bound states.