What does 'eqv' do exactly?

I've searched the archives, but did not see a good explanation of what eqv does, and what is meant by snapshotting in the description of the synopses.

Can anyone explain it (with examples?) or point to an existing treatment, please?

--John

• What does 'eqv' do exactly? by John M. Dlugosz
• Re: What does 'eqv' do exactly? by Adriano Ferreira
• Re: What does 'eqv' do exactly? by John M. Dlugosz
• Re: What does 'eqv' do exactly? by Jon Lang
• Re: What does 'eqv' do exactly? by John M. Dlugosz
• Re: What does 'eqv' do exactly? by TSa
• Re: What does 'eqv' do exactly? by David Green
• Re: What does 'eqv' do exactly? by Jon Lang