Does the 'is sister of' relation demonstrate symmetry in mathematics?

💡 The Answer

• The relation 'is sister of' holds between Marie Curie and Bronisława Dłuska.
• It also holds vice versa, showing symmetry.
• Symmetry means if A is sister of B, then B is sister of A.
• This contrasts with asymmetric relations like 'is less than'.
• Symmetric relations are common in kinship and equivalence.