(1) <(x1+x3)^(2n)> == Catalan(n) for n = 0..20: True
(2) <(M-U-D)^n 1> == 0 for n = 1..24: True
(3) R B R == B, U f in Q[x3,s], D f in Q[x1,s] on monomials a,b <= 4, c <= 2: True
ALL OK
nice -n 10 venv/bin/python   0.19s user 0.01s system 98% cpu 0.202 total
