> >> >The first proposition is of the form: "no sample shall >> have property A >> >or property B" >> >This is equivalent to "all samples shall not have property >> A AND not >> >have property B". >> >> That WOULD be true if it were not for the thickness specifications, >> which make it impossible for A and B to apply to the same sample.
Condition A refers to the two lines which mention thickness and which are indeed mutually exclusive. Condition B refers to the line mentioning to the 100 mm. >> It is necessary to be VERY careful when changing a text >> that includes >> 'or' and/or 'and' from positive to negative or vice versa. I must confess that I do not know antyhing about HB material, but that I did study proposition logic. This branch of mathematics provides the tools needed to handle these kind of issues. My email was not intended to make any statement about what is HB or what isn't, it was only intended to warn that the text quoted from UL60950, Third Edition, A.8.5 Compliance criteria is not equivalent to the text quoted from Cl. 7.1 of the 5th edition of UL94: 1997. Leen Mak Network Solutions Group - Standards and Industry Relations Lucent Technologies Hilversum - The Netherlands tel. +31 35 687 4143 email [email protected] - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
