Faddeev Isgur

Algebraic Formalism
Dynamics S Matrix Unitarity


Pre 1980
LOvelace piN
Cutkowsky pi N
Cashmore pi pi N Isobar

Peripheral
Ascoli (A1)
Aitchison
LASS ?
Halzen
X(n1n2)
X(n1n2n3)

After 1980
E852
XBarrel
Pittsburgh

Chung
Klempt
Sparrier
Dytman

Isobar
Kmatrix corrections - large numerically but conclusions unchanged

piN algebraic optimized by Cutkowsky
pipiN "direct channel duality"

2 PLUS cross channel unitarity
3 PLUS cross and direct

Make Model
Find amplitudes
Interpret amplitudes

Much more data
Much better computing -- "tools NOT power"