<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.6000.16809" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT face="Courier New" size=2>Equality is a very tedious thing to define. But replacing f by <FONT face="Times New Roman" size=3>(lambda(x) (+(* 3 x) 5))) does produce the same results (normally (i.e. if. for example `'lamda' is not redefined)) In mathematics two functions are connsidered to be the same if they produce the same results for the same arguments (which already presuposes an equality relation). In Scheme, this concept is somewhat more complicated because it cannot always be proven whether or not two functions always produce the same results when given the same arguments. Because of the difficulty of deciding when two functuions are the same, we have for example:</FONT></FONT></DIV> <DIV>(equal? (lambda (x) x) (lambda (x) x)) --> #f, whereas a mathematicean probably would ansewer `yes'.</DIV> <DIV>Jos</DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style="FONT: 10pt arial">----- Original Message ----- </DIV> <DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B> <A title=adityashukla1983@gmail.com href="mailto:adityashukla1983@gmail.com">aditya shukla</A> </DIV> <DIV style="FONT: 10pt arial"><B>To:</B> <A title=plt-scheme@list.cs.brown.edu href="mailto:plt-scheme@list.cs.brown.edu">plt-scheme@list.cs.brown.edu</A> </DIV> <DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, February 13, 2009 9:05 PM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> [plt-scheme] Understanding lambda</DIV> <DIV><BR></DIV>I am trying to understand lambda and i have a question.<BR><BR>Suppose (define f (lambda(x) (+(* 3 x) 5)))<BR><BR>Now i have read and heard that lambda is used to define unnamed functions now , i am confused about the value of f<BR>ie will it be equal to the function returned by (lambda(x) (+(* 3 x) 5)) or will be equal to the value which is computed for any value of x ie if x =1 then f =8.Any help is appreciated.<BR><BR>Thanks in advance<BR><BR>Aditya<BR><BR> <P> <HR> <P></P>_________________________________________________<BR>  For list-related administrative tasks:<BR>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme<BR></BLOCKQUOTE></BODY></HTML>