A recent forum thread went into a long disussion of simultaneity. The term "ansible line" was used (later referred to as a "simultaneity line.") Einstein demonstrated with a thought experiment with regards to lightning and a moving train that events can be simultaneous in one time frame but not so in others. 1) Can two events which are simultaneous in one frame of reference (FOR) be simultaneous in another - that is - THE SAME TWO EVENTS, or is the simultaneity limited to only ONE FOR. 2) Can one always find an FOR in which any two event pairs are simultaneous? 3) It would seem that an event A can be simultaneous with an event B in one FOR and also be simultaneous with event C in a second FOR. This does not mean that B and C are simultaneous but it should be possible to find an FOR in which they are. Again, this would NOT mean that [tex]\exists[/tex] an FOR in which A, B and C are simultaneous mutually, or does it?