2 votes 2 votes Total onto function from a to b with cardinality 4 and 3 respectively?? Set Theory & Algebra discrete-mathematics functions + – anshu asked Feb 7, 2015 • edited Nov 29, 2023 by Hira Thakur anshu 855 views answer comment Share Follow See all 0 reply Please log in or register to add a comment.
3 votes 3 votes 3! * S(4, 3) = 3! * 6 = 36 https://gateoverflow.in/5596/no-of-surjective-functions http://www.math.uiuc.edu/~kostochk/math413/comb.pdf Arjun answered Feb 8, 2015 Arjun comment Share Follow See all 2 Comments See all 2 2 Comments reply anshu commented Feb 8, 2015 reply Follow Share It should be 24 by the following reasoning: an element in b has 4 choices to be matched to an element in set a but then that element will not be matched to any other element in set A because it is a function.now another element in set B can be matched to any of the remaining element in set A and so on so answer should be 4*3*2×1=24 0 votes 0 votes Arjun commented Feb 9, 2015 reply Follow Share @anshu That works only if number of elements in A and B are the same - or if we are counting bijective mappings and not surjective. 1 votes 1 votes Please log in or register to add a comment.
