, and Ross Street
, and Ross Street
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和罗斯街
DOI:
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发表时间:
2005
期刊:
影响因子:
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通讯作者:
Weinstein Sp
中科院分区:
文献类型:
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作者:
C. Aw;Weinstein Sp
The purpose of this work is to highlight the notions of lax braiding and lax centre for monoidal categories and more generally for promonoidal categories. Lax centres are lax braided. Generally the centre is a full subcategory of the lax centre, however we show that it is sometimes the case that the two coincide. We identify lax centres of monoidal functor categories in various cases. Introduction Braidings for monoidal categories were introduced in [JS1] and its forerunners. The centre ZX of a monoidal category X was introduced in [JS0] in the process of proving that the free tortile monoidal category has another universal property. The centre of a monoidal category is a braided monoidal category. What we now call lax braidings were considered tangentially by Yetter [Yet]. What we now call the lax centre ZlX of X was considered under the name “weak centre” by P. Schauenburg [Sch]. The purpose of this work is to highlight the notions of lax braiding and lax centre for monoidal categories X and more generally for promonoidal categories C . Lax centres turn out to be lax braided monoidal categories. Generally the centre is a full subcategory of the lax centre, however it is sometimes the case that the two coincide. We have two such theorems under different hypotheses, one in the case sufficient dual objects exist in the additive context, and the other in the cartesian context. For a promonoidal category C , we relate the lax centre of the [Day] convolution on C to the convolution on the lax centre of C . Indeed, sometimes these are equivalent. One reason for being interested in the lax centre of X is that, if an object X of X is equipped with the structure of monoid in ZlX , then tensoring with X defines a monoidal endofunctor −⊗X of X ; this has applications in cases where the lax centre can be explicitly identified. 1991 Mathematics Subject Classification. Primary 18D10; Secondary 18D20, 16W30, 20L17.