如果您想练习实现递归谓词，可以使用

If you want to practise implementing recursive predicates, you could proceed like this using dcg:

matrix_transposed_items(Mss,Xs) :-
   notlonger_than(Mss,Xs),
   phrase(matrix_tconcat(Mss),Xs).

matrix_tconcat([]) --> [].
matrix_tconcat([Cs|Css]) -->
   row_rows_rest_(Cs,Css,Mss),
   matrix_tconcat(Mss).

row_rows_rest_([],Css,[]) --> 
   { emptylists(Css) }.
row_rows_rest_([X|Xs],Xss,[Xs|Mss]) -->
   [X],
   nonemptyrows_rest(Xss,Mss).

nonemptyrows_rest([],[]) --> [].
nonemptyrows_rest([[X|Xs]|Xss],[Xs|Mss]) -->
   [X],
   nonemptyrows_rest(Xss,Mss).

以上代码基于三个辅助谓词，可以这样定义:

Above code is based on three auxiliary predicates which can be defined like this:

nil_or_cons([]).
nil_or_cons([_|_]).

notlonger_than([],Bs) :-
   nil_or_cons(Bs).
notlonger_than([_|As],[_|Bs]) :-
   notlonger_than(As,Bs).

emptylists([]).
emptylists([[]|Xs]) :-
   emptylists(Xs).

让我们运行一些查询！首先，我们使用一些二次矩阵:

Let's run some queries! First, we use some quadratic matrix:

?- matrix_transposed_items([[1,2,3],[4,5,6],[7,8,9]],Xs).
Xs = [1,4,7,2,5,8,3,6,9].                            % succeeds deterministically

接下来，OP提供的非二次用例:

Next, the non-quadratic use-cases the OP gave:

?- matrix_transposed_items([[a,b],[c,d],[e,f]],Ls).
Ls = [a,c,e,b,d,f].                                  % succeeds deterministically

?- matrix_transposed_items([[1,2,3],[4,5,6]],Ls).
Ls = [1,4,2,5,3,6].                                  % succeeds deterministically

我们也尝试去其他方向"！

Let's try going the "other direction", too!

?- matrix_transposed_items(Mss,[1,2,3,4,5,6,7,8,9,10]).
  Mss = [[1,2,3,4,5,6,7,8,9,10]]
; Mss = [[1,3,5,7,9],[2,4,6,8,10]]
; Mss = [[1,6],[2,7],[3,8],[4,9],[5,10]]
; Mss = [[1],[2],[3],[4],[5],[6],[7],[8],[9],[10]]
; false.                                             % terminates universally