Arkadiusz Jadczyk
Jun29-04, 05:53 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>I am reading "Emergence of time" by Michael Heller and Wieslaw Sassin:\n\nhttp://arxiv.org/abs/gr-qc/9711051\n\nUnfortunately I have no experience with groupoids and have to fight with\neach new concept and definition. And so I have a problem with the very\nfirst formula on page 3, where the convolution product is defined.\n\n1) The authors define the product for functions. it seems to me that the\nproduct (using integration) needs half-densities, not functions.\n\n2) For the two arguments gamma1,gamma2 the authors write gamma1,gamma2\n\\in G_p. It seems to me that only one of the arguments, gamma1 is in the\nfibre.\n\nOf course these are elementary things for an expert, and probably not\nthat important for the rest of the paper, yet any help with the above\nwill be appreciated.\n\nark\n--\n\nArkadiusz Jadczyk\nhttp://www.cassiopaea.org/quantum_future/homepage.htm\n\n--\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>I am reading "Emergence of time" by Michael Heller and Wieslaw Sassin:
http://arxiv.org/abs/http://www.arxiv.org/abs/gr-qc/9711051
Unfortunately I have no experience with groupoids and have to fight with
each new concept and definition. And so I have a problem with the very
first formula on page 3, where the convolution product is defined.
1) The authors define the product for functions. it seems to me that the
product (using integration) needs half-densities, not functions.
2) For the two arguments gamma1,gamma2 the authors write gamma1,gamma2
\in G_p. It seems to me that only one of the arguments, gamma1 is in the
fibre.
Of course these are elementary things for an expert, and probably not
that important for the rest of the paper, yet any help with the above
will be appreciated.
ark
--
Arkadiusz Jadczyk
http://www.cassiopaea.org/quantum_future/homepage.htm
--
http://arxiv.org/abs/http://www.arxiv.org/abs/gr-qc/9711051
Unfortunately I have no experience with groupoids and have to fight with
each new concept and definition. And so I have a problem with the very
first formula on page 3, where the convolution product is defined.
1) The authors define the product for functions. it seems to me that the
product (using integration) needs half-densities, not functions.
2) For the two arguments gamma1,gamma2 the authors write gamma1,gamma2
\in G_p. It seems to me that only one of the arguments, gamma1 is in the
fibre.
Of course these are elementary things for an expert, and probably not
that important for the rest of the paper, yet any help with the above
will be appreciated.
ark
--
Arkadiusz Jadczyk
http://www.cassiopaea.org/quantum_future/homepage.htm
--