"x = A -> ( ph <-> ps )" would be the way to state with an implicit substitution the same thing as “[. A / x ]. ph <-> ps” states explicitly, that is “ps is the result of taking all instances of ‘x’ in ph, and substituting them with ‘A’.”
My experience is that implicit substitution is more easy to work with. _ Thierry -- You received this message because you are subscribed to the Google Groups "Metamath" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/metamath/C75D13C7-86B0-4352-8474-46FC1371DC75%40gmx.net.
