NIELIT Scientist B 2020 November: 115

Question

Considering binary relationships, possible cardinality ratios are:

• A. one:one
• B. $1:N$
• C. $M:N$
• D. All the options

Answer 1

A binary relation is not a binary operation (groups, monoids).

A binary relation on X and Y, is simply a subset of $X \times Y$.

A binary operation on X is a mapping from $ X \times X \rightarrow X $.

So any of the first 3 options are possible.