[math-fun] Logic question

... are suppositions necessary for logical arguments?

Thomason, "Symbolic Logic" (Collier-Macmillan, 1970), shows a procedure for removing a supposition from a proof (p68-69). That mechanical process (at least) triples the length of the proof-part within the supposition. I suppose something similar applies to any proof system. -- Don Reble djr@nk.ca