# Mathematics

//Mathematics

Mathematical science

## On Tzimtzum, Sefirot and Cardinal Numbers

Today is Yud Tes Kislev -- Rosh HaShanah of Chasidut. Today I received two gifts, which I'd like to share. Lately, while learning Samach Vov, I've been struggling to understand the meaning of Sefirot Ein Keitz. Today, during shacharis shemone esreh, it donned upon me that the literal meaning of Sefirot Ein Keitz is infinite numbers. I suddenly realized that while Sefirot after the Tzimtzum are ordinary numbers, Sefirot before Tzimtzum—Sefirot Ein Keitz—are cardinal numbers developed by the mathematician Georg Cantor at the end of the 19 c. Later during the day, I got the second epiphany that Tzimtzum is the collapse of the universal wavefunction describing the creation. Before Tzimtzum, all creations were in the state of "yecholot" -- potentialities. After the Tzimtzum, i.e., after the collapse of the wavefuction, these potentialities actualized in specific [...]

## Forty Two Journeys to the Answer to the Ultimate Question of Life, the Universe, and Everything

These are the journeys of the children of Israel… (Numbers 33:1) When G-d brought the Jews out from Egypt, He brought them out with the mystery of the 42-letter name, just as He created heaven and earth… (Zohar Chadash) The forty-two "stations" from Egypt to the Promised Land are replayed in the life of every individual Jew, as his soul journeys from its descent to earth at birth to its return to its Source. (Rabbi Israel Baal Shem Tov) Torah portion Massei (Num. 33-35) recalls forty-two journeys of the Children of Israel in the Sinai desert after the Exodus from Egypt.  This is not the first time the concept of forty-two journeys appears in the Torah.  Commenting on the Biblical verse, “And God said, ‘Behold, I Will Cause to Rain Bread from Heaven for You,’” (Ex. 25:5) the Midrash [...]

## Creatio ex Nihilo and the Number Theory

As we began this Shabbat reading the Fourth Book of Torah—Numbers, I thought, it would be appropriate to post on this blog an excerpt from my article Creatio ex Nihilo, Number Theory, Quantum Vacuum, and the Big Bang, originally published in B’Or HaTorah (Jerusalem: 2007, No. 17, p.115). Introduction The kabbalistic principle of yesh m’ayin or creatio ex nihilo—creation of something from nothing—is difficult to fully understand because we have no experience of creating something from nothing. Although many human creative activities seem to create something new, in fact, they merely change the form or nature of things. Never do we create something from nothing. A sculptor takes a preexisting slab of marble and shapes it according to his imagination. So does a potter, who molds pottery out of clay; a glassblower, who forms liquid [...]