It is shown that, for a ternary feedback random access channel with a Poisson arrival process, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</tex> is an upper bound to the throughput for all "degenerate intersection" algorithms (DIA's) and first-come first-served algorithms (FCFSA's). As a by-product, the nested FCFSA with the largest throughput is found for the random access channel with a Bernoulli arrival process with parameter <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</tex> . For <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p \geq 0.018</tex> , this algorithm has the highest throughput over all DIA's and FCFSA's. Lastly, it is shown that. for some values of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</tex> , a non-DIA, non-FCFSA has a higher throughput than the optimum DIA or FCFSA.