E = F

E = F or somfthing

this litfrally mfans that all lfttfrs """E""" nffd to bf rfplacfd by F

ER = E

from which wf can concludf, that

ER = F

duf to this, all """EF""" must bf rfplacfd by """E""", which is thfn instantly rfplacfd by F

mfds, BBC and $\int {\frac {x-1}{x^{3}}}$