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f calculates the number of 0-1 matrices with row sums A and column sums B.

fricas
f(A:List PI, B:List PI): FRAC INT == cap(reduce(*, [elementary i for i in A]), reduce(*, [complete i for i in B]))
Function declaration f : (List(PositiveInteger),List(PositiveInteger )) -> Fraction(Integer) has been added to workspace.
Type: Void

For example, there are

fricas
f([2,2,2,2], [2,3,3])
fricas
Compiling function f with type (List(PositiveInteger),List(
      PositiveInteger)) -> Fraction(Integer)

\label{eq1}12(1)
Type: Fraction(Integer)

0-1 matrices whose rows all sum up to two and whose first column has 2 entries equal to one, the others having 3 entries equal to one.




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