The article seems to be full of little mistakes. A torus has Betti number β1 of 2, not 1 as is on the text. Also, β1 and genus are not "equal", they are related

The article seems to be full of little mistakes. A torus has Betti number β1 of 2, not 1 as is on the text. Also, β1 and genus are not "equal", they are related by β1 = 2g. Furthermore, the Euler charasteric also doesn't "equal" it. Euler charasteristic χ in terms of genus is χ = 2 − 2g, so by substitution, χ = 2 − β1.