GATE CSE 1993 | Question: 8.6

Question

Let $A$ and $B$ be sets with cardinalities $m$ and $n$ respectively. The number of one-one mappings from $A$ to $B$, when $m < n$, is

• A. $m^n$
• B. $^nP_m$
• C. $^mC_n$
• D. $^nC_m$
• E. $^mP_n$

Answer 1

Answer: B
Ref: Page $33$ of http://www.cs.toronto.edu/~stacho/macm101-2.pdf

Comments

Ref:

Answer 2

one to one mapping is permutations of m different thing out of n different thing..
P(n,m)

Answer 3

Option B