I love Liz Hawley. She is Himalaya climbing history defined. From this article, she seems to have a definition of climbing solo.

Liz stressed that being solo is to be truly isolated. And she went a step further; saying that perhaps one shouldn’t even talk to other people over radio or sat phone. But then she hesitated; "this was perhaps to go to the extremes", she figured.

Self-sufficiency is a matter of great pride to seasoned explorers; often more important than the goal itself. Only when you are self-sufficient and alone, will your solo claim be accepted.

Dunno, lots to agree with and disagree. I 'soloed' Mescalito (among other routes) on El Cap. Were there tons of people around me? Yes. Did I climb, clean, haul every pitch? Yes. Would I say I soloed? Yes. So I pass the self-sufficiency, but not the solitude. I think it's ridiculous in this day and age to have solitude as a criteria for a true solo. I'm torn, don't know how to approach this one, I mean going against Liz Hawley is like going bareback on the first date, not putting lemon on your fish, not saluting the flag - you just don't do it.