How many holes does a straw have? (Mathematical proof)

11:43 AM    Algebraic Topology , Mathematics , Topology   

Q. How many holes does a straw have? (Mathematical proof) 

1 hole —A straw is topologically equivalent to S¹× [0, L], where S¹ is a unit circle and L is the length of the straw. Since S¹ has 1 hole, and [0, L] has no holes, a straw has 1 hole.

Drinking Straws: How Many Holes?

Answer: One

A straw is a circle with a certain length. As we all know that a circle is having only one hole so is the straw.

Does a straw have 2 holes or 1 hole?

A straw has two openings but only one hole.