while this ((a*b)/c)^5 /. (a_^n_.*b_^n_.)/c_^n_. :> (1/x)^n does not

I think to remember that I had seen a polygon (triangle) reduction algorithm somewhere here. But I can not find it. What I am looking for is a post where a mesh with a certain mesh cell count was reduced by merging cells. Maybe I am imagining things, or does anyone else remember the post and can point me to it? Thx.

@bmf, thx never the less

@bmf It's often instructive to look at the FullForm of the involved expressions:

FullForm[(a*b)^5]
(* Times[Power[a,5],Power[b,5]] *)

FullForm[a_^n_.*b_^n_.]
(* Times[Power[Pattern[a,Blank[]],Optional[Pattern[n,Blank[]]]],Power[Pattern[b,Blank[]],Optional[Pattern[n,Blank[]]]]] *)

FullForm[((a*b)/c)^5]
(* Times[Power[a,5],Power[b,5],Power[c,-5]] *)

FullForm[(a_^n_.*b_^n_.)/c_^n_.]
(* Times[Power[Pattern[a,Blank[]],Optional[Pattern[n,Blank[]]]],Power[Pattern[b,Blank[]],Optional[Pattern[n,Blank[]]]],Power[Pattern[c,Blank[]],Times[-1,Optional[Pattern[n,Blank[]]]]]] *)

(Note the difference between Power[c,-5] and Power[..., Times[-1, ...]])

@user21 Maybe this?

@rm-rf, thanks. That's not the one - I must be imaging things. Thanks for looking, much appreciated!