We show that several classical bilateral summation and transformation
formulas have semi-finite forms. We obtain these semi-finite forms from
unilateral summation and transformation formulas. Our method can be applied to
derive Ramanujan's 1​ψ1​ summation, Bailey's 2​ψ2​ transformations,
and Bailey's 6​ψ6​ summation.Comment: 8 pages. accepted by Proc. Amer. Math. So