bi.bldim>

Theorem.

Arguments:

phi (pr), psi (pr), chi (pr),

Hypotheses:

(phileftrightarrowpsi)

Assertions:

((chitophi)leftrightarrow(chitopsi))

Proof:

Hyp Ref Line Expr
Hypo1(phileftrightarrowpsi)
1bi>2(phitopsi)
2syl<3((chitophi)to(chitopsi))
1bi<4(psitophi)
4syl<5((chitopsi)to(chitophi))
3, 5>bii6((chitophi)leftrightarrow(chitopsi))